Scala Standard Library2.12.2 < Back
 

# Packages

-  package root

  This is the documentation for the Scala standard library.

  This is the documentation for the Scala standard library.

  #### Package structure

  The scala package contains core types like `Int`, `Float`, `Array` or `Option` which are accessible in all Scala compilation units without explicit qualification or imports.

  Notable packages include:

  - `scala.collection` and its sub-packages contain Scala's collections framework
    - `scala.collection.immutable` - Immutable, sequential data-structures such as `Vector`, `List`, `Range`, `HashMap` or `HashSet`
    - `scala.collection.mutable` - Mutable, sequential data-structures such as `ArrayBuffer`, `StringBuilder`, `HashMap` or `HashSet`
    - `scala.collection.concurrent` - Mutable, concurrent data-structures such as `TrieMap`
    - `scala.collection.parallel.immutable` - Immutable, parallel data-structures such as `ParVector`, `ParRange`, `ParHashMap` or `ParHashSet`
    - `scala.collection.parallel.mutable` - Mutable, parallel data-structures such as `ParArray`, `ParHashMap`, `ParTrieMap` or `ParHashSet`
  - `scala.concurrent` - Primitives for concurrent programming such as `Futures` and `Promises`
  - `scala.io` - Input and output operations
  - `scala.math` - Basic math functions and additional numeric types like `BigInt` and `BigDecimal`
  - `scala.sys` - Interaction with other processes and the operating system
  - `scala.util.matching` - Regular expressions

  Other packages exist. See the complete list on the right.

  Additional parts of the standard library are shipped as separate libraries. These include:

  - `scala.reflect` - Scala's reflection API (scala-reflect.jar)
  - `scala.xml` - XML parsing, manipulation, and serialization (scala-xml.jar)
  - `scala.swing` - A convenient wrapper around Java's GUI framework called Swing (scala-swing.jar)
  - `scala.util.parsing` - Parser combinators (scala-parser-combinators.jar)

  #### Automatic imports

  Identifiers in the scala package and the `scala.Predef` object are always in scope by default.

  Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example, `List` is an alias for `scala.collection.immutable.List`.

  Other aliases refer to classes provided by the underlying platform. For example, on the JVM, `String` is an alias for `java.lang.String`.

  Definition Classes
    root
-  package scala

  Core Scala types.

  Core Scala types. They are always available without an explicit import.

  Definition Classes
    root
-  package collection

  Contains the base traits and objects needed to use and extend Scala's collection library.

  Contains the base traits and objects needed to use and extend Scala's collection library.

  #### Guide

  A detailed guide for using the collections library is available at http://docs.scala-lang.org/overviews/collections/introduction.html. Developers looking to extend the collections library can find a description of its architecture at http://docs.scala-lang.org/overviews/core/architecture-of-scala-collections.html.

  #### Using Collections

  It is convenient to treat all collections as either a scala.collection.Traversable or scala.collection.Iterable, as these traits define the vast majority of operations on a collection.

  Collections can, of course, be treated as specifically as needed, and the library is designed to ensure that the methods that transform collections will return a collection of the same type:

      scala> val array = Array(1,2,3,4,5,6)
      array: Array[Int] = Array(1, 2, 3, 4, 5, 6)

      scala> array map { _.toString }
      res0: Array[String] = Array(1, 2, 3, 4, 5, 6)

      scala> val list = List(1,2,3,4,5,6)
      list: List[Int] = List(1, 2, 3, 4, 5, 6)

      scala> list map { _.toString }
      res1: List[String] = List(1, 2, 3, 4, 5, 6)

  #### Creating Collections

  The most common way to create a collection is to use its companion object as a factory. The three most commonly used collections are scala.collection.Seq, scala.collection.immutable.Set, and scala.collection.immutable.Map. They can be used directly as shown below since their companion objects are all available as type aliases in either the scala package or in `scala.Predef`. New collections are created like this:

      scala> val seq = Seq(1,2,3,4,1)
      seq: Seq[Int] = List(1, 2, 3, 4, 1)

      scala> val set = Set(1,2,3,4,1)
      set: scala.collection.immutable.Set[Int] = Set(1, 2, 3, 4)

      scala> val map = Map(1 -> "one", 2 -> "two", 3 -> "three", 2 -> "too")
      map: scala.collection.immutable.Map[Int,String] = Map(1 -> one, 2 -> too, 3 -> three)

  It is also typical to prefer the scala.collection.immutable collections over those in scala.collection.mutable; the types aliased in the `scala.Predef` object are the immutable versions.

  Also note that the collections library was carefully designed to include several implementations of each of the three basic collection types. These implementations have specific performance characteristics which are described in the guide.

  The concrete parallel collections also have specific performance characteristics which are described in the parallel collections guide

  ##### Converting to and from Java Collections

  The scala.collection.JavaConverters object provides a collection of decorators that allow converting between Scala and Java collections using `asScala` and `asJava` methods.

  Definition Classes
    scala
-  package concurrent
  Definition Classes
    collection
-  package convert
  Definition Classes
    collection
-  package generic
  Definition Classes
    collection
-  package immutable
  Definition Classes
    collection
-  package mutable
  Definition Classes
    collection
-  package parallel

  Package object for parallel collections.

  Package object for parallel collections.

  Definition Classes
    collection
-  package script
  Definition Classes
    collection
- +:
- :+
- AbstractIterable
- AbstractIterator
- AbstractMap
- AbstractSeq
- AbstractSet
- AbstractTraversable
- BitSet
- BitSetLike
- BufferedIterator
- CustomParallelizable
- DefaultMap
- GenIterable
- GenIterableLike
- GenMap
- GenMapLike
- GenSeq
- GenSeqLike
- GenSet
- GenSetLike
- GenTraversable
- GenTraversableLike
- GenTraversableOnce
- IndexedSeq
- IndexedSeqLike
- IndexedSeqOptimized
- Iterable
- IterableLike
- IterableProxy
- IterableProxyLike
- IterableView
- IterableViewLike
- Iterator
- JavaConversions
- JavaConverters
- LinearSeq
- LinearSeqLike
- LinearSeqOptimized
- Map
- MapLike
- MapProxy
- MapProxyLike
- Parallel
- Parallelizable
- Searching
- Seq
- SeqLike
- SeqProxy
- SeqProxyLike
- SeqView
- SeqViewLike
- Set
- SetLike
- SetProxy
- SetProxyLike
- SortedMap
- SortedMapLike
- SortedSet
- SortedSetLike
- Traversable
- TraversableLike
- TraversableOnce
- TraversableProxy
- TraversableProxyLike
- TraversableView
- TraversableViewLike
- ViewMkString

t

scala.collection

# MapProxyLike 

###

#### trait MapProxyLike[A, +B, +This <: MapLike[A, B, This] with Map[A, B]] extends MapLike[A, B, This] with IterableProxyLike[(A, B), This]

This trait implements a proxy for Map objects. It forwards all calls to a different Map object.

Annotations
  @deprecated
Deprecated

  (Since version 2.11.0) proxying is deprecated due to lack of use and compiler-level support

Source
  MapProxyLike.scala
Version

  2.8

Since

  2.8

Linear Supertypes
IterableProxyLike[(A, B), This], TraversableProxyLike[(A, B), This], Proxy, MapLike[A, B, This], Subtractable[A, This], GenMapLike[A, B, This], IterableLike[(A, B), This], GenIterableLike[(A, B), This], TraversableLike[(A, B), This], GenTraversableLike[(A, B), This], Parallelizable[(A, B), ParMap[A, B]], TraversableOnce[(A, B)], GenTraversableOnce[(A, B)], FilterMonadic[(A, B), This], HasNewBuilder[(A, B), This], Equals, PartialFunction[A, B], (A) ⇒ B, AnyRef, Any
Known Subclasses
MapProxy, MapProxy, MapProxy
 
Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. MapProxyLike
2. IterableProxyLike
3. TraversableProxyLike
4. Proxy
5. MapLike
6. Subtractable
7. GenMapLike
8. IterableLike
9. GenIterableLike
10. TraversableLike
11. GenTraversableLike
12. Parallelizable
13. TraversableOnce
14. GenTraversableOnce
15. FilterMonadic
16. HasNewBuilder
17. Equals
18. PartialFunction
19. Function1
20. AnyRef
21. Any

Implicitly

1. by CollectionsHaveToParArray
2. by MonadOps
3. by any2stringadd
4. by StringFormat
5. by Ensuring
6. by ArrowAssoc
7. by alternateImplicit

1. Hide All
2. Show All

Visibility

1. Public
2. All

### Type Members

1.  class DefaultKeySet extends AbstractSet[K] with Set[K] with Serializable

   The implementation class of the set returned by `keySet`.

   The implementation class of the set returned by `keySet`.

   Attributes
     protected
   Definition Classes
     MapLike
2.  class DefaultValuesIterable extends AbstractIterable[V] with Iterable[V] with Serializable

   The implementation class of the iterable returned by `values`.

   The implementation class of the iterable returned by `values`.

   Attributes
     protected
   Definition Classes
     MapLike
3.  class FilteredKeys extends AbstractMap[K, V] with DefaultMap[K, V]
   Attributes
     protected
   Definition Classes
     MapLike
4.  class MappedValues [W] extends AbstractMap[K, W] with DefaultMap[K, W]
   Attributes
     protected
   Definition Classes
     MapLike
5.  type Self = This

   The type implementing this traversable

   The type implementing this traversable

   Attributes
     protected[this]
   Definition Classes
     TraversableLike
6.  class WithFilter extends FilterMonadic[A, Repr]

   A class supporting filtered operations.

   A class supporting filtered operations. Instances of this class are returned by method `withFilter`.

   Definition Classes
     TraversableLike

### Abstract Value Members

1.  abstract def empty: This

   The empty map of the same type as this map

   The empty map of the same type as this map

   returns

     an empty map of type `This`.

   Definition Classes
     MapLike
2.  abstract def self: This
   Definition Classes
     TraversableProxyLike → Proxy
3.  abstract def seq: Map[A, B]
   Definition Classes
     GenMapLike → Parallelizable → GenTraversableOnce

### Concrete Value Members

1.  final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

     `true` if !(this == that), false otherwise.

   Definition Classes
     AnyRef → Any
2.  final def ##(): Int

   Equivalent to `x.hashCode` except for boxed numeric types and `null`.

   Equivalent to `x.hashCode` except for boxed numeric types and `null`. For numerics, it returns a hash value which is consistent with value equality: if two value type instances compare as true, then ## will produce the same hash value for each of them. For `null` returns a hashcode where `null.hashCode` throws a `NullPointerException`.

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any
3.  def +(kvs: (K, V)*): Map[K, V]

   [use case] Adds key/value pairs to this map, returning a new map.

   [use case]

   Adds key/value pairs to this map, returning a new map.

   This method takes two or more key/value pairs. Another overloaded variant of this method handles the case where a single key/value pair is added.

   kvs

     the key/value pairs

   returns

     a new map with the given bindings added to this map

   Definition Classes
     MapProxyLike → MapLike
    Full Signature

   #### def +[B1 >: B](kv1: (A, B1), kv2: (A, B1), kvs: (A, B1)*): Map[A, B1]

4.  def +(kv: (K, V)): Map[K, V]

   [use case] Adds a key/value pair to this map, returning a new map.

   [use case]

   Adds a key/value pair to this map, returning a new map.

   kv

     the key/value pair

   returns

     a new map with the new binding added to this map

   Definition Classes
     MapProxyLike → MapLike → GenMapLike
    Full Signature

   #### def +[B1 >: B](kv: (A, B1)): Map[A, B1]

5.  def ++(xs: Traversable[(K, V)]): Map[K, V]

   [use case] Adds all key/value pairs in a traversable collection to this map, returning a new map.

   [use case]

   Adds all key/value pairs in a traversable collection to this map, returning a new map.

   xs

     the collection containing the added key/value pairs

   returns

     a new map with the given bindings added to this map

   Definition Classes
     MapProxyLike → MapLike
    Full Signature

   #### def ++[B1 >: B](xs: GenTraversableOnce[(A, B1)]): Map[A, B1]

6.  def ++[B >: (A, B), That](xs: GenTraversableOnce[B])(implicit bf: CanBuildFrom[This, B, That]): That

   Returns a new traversable collection containing the elements from the left hand operand followed by the elements from the right hand operand.

   Returns a new traversable collection containing the elements from the left hand operand followed by the elements from the right hand operand. The element type of the traversable collection is the most specific superclass encompassing the element types of the two operands.

   B

     the element type of the returned collection.

   That

     the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

   bf

     an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and the new element type `B`.

   returns

     a new collection of type `That` which contains all elements of this traversable collection followed by all elements of `that`.

   Definition Classes
     TraversableProxyLike → TraversableLike → GenTraversableLike
7.  def ++:[B >: (A, B), That](that: Traversable[B])(implicit bf: CanBuildFrom[This, B, That]): That

   As with `++`, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

   As with `++`, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

   It differs from `++` in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.

   Example:

       scala> val x = List(1)
       x: List[Int] = List(1)

       scala> val y = LinkedList(2)
       y: scala.collection.mutable.LinkedList[Int] = LinkedList(2)

       scala> val z = x ++: y
       z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)

   This overload exists because: for the implementation of `++:` we should reuse that of `++` because many collections override it with more efficient versions.

   Since `TraversableOnce` has no `++` method, we have to implement that directly, but `Traversable` and down can use the overload.

   B

     the element type of the returned collection.

   That

     the class of the returned collection. Where possible, `That` is the same class as the current collection class `Repr`, but this depends on the element type `B` being admissible for that class, which means that an implicit instance of type `CanBuildFrom[Repr, B, That]` is found.

   that

     the traversable to append.

   bf

     an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and the new element type `B`.

   returns

     a new collection of type `That` which contains all elements of this traversable collection followed by all elements of `that`.

   Definition Classes
     TraversableLike
8.  def ++:[B](that: TraversableOnce[B]): Map[B]

   [use case] As with `++`, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

   [use case]

   As with `++`, returns a new collection containing the elements from the left operand followed by the elements from the right operand.

   It differs from `++` in that the right operand determines the type of the resulting collection rather than the left one. Mnemonic: the COLon is on the side of the new COLlection type.

   Example:

       scala> val x = List(1)
       x: List[Int] = List(1)

       scala> val y = LinkedList(2)
       y: scala.collection.mutable.LinkedList[Int] = LinkedList(2)

       scala> val z = x ++: y
       z: scala.collection.mutable.LinkedList[Int] = LinkedList(1, 2)

   B

     the element type of the returned collection.

   that

     the traversable to append.

   returns

     a new map which contains all elements of this map followed by all elements of `that`.

   Definition Classes
     TraversableLike
    Full Signature

   #### def ++:[B >: (A, B), That](that: TraversableOnce[B])(implicit bf: CanBuildFrom[This, B, That]): That

9.  def -(key: K): Map[K, V]

   [use case] Removes a key from this map, returning a new map.

   [use case]

   Removes a key from this map, returning a new map.

   key

     the key to be removed

   returns

     a new map without a binding for `key`

   Definition Classes
     MapProxyLike → MapLike → Subtractable → GenMapLike
    Full Signature

   #### def -(key: A): This

10.  def -(elem1: A, elem2: A, elems: A*): This

    Creates a new collection from this collection with some elements removed.

    Creates a new collection from this collection with some elements removed.

    This method takes two or more elements to be removed. Another overloaded variant of this method handles the case where a single element is removed.

    elem1

      the first element to remove.

    elem2

      the second element to remove.

    elems

      the remaining elements to remove.

    returns

      a new collection that contains all elements of the current collection except one less occurrence of each of the given elements.

    Definition Classes
      Subtractable
11.  def --(xs: GenTraversableOnce[A]): This

    Creates a new collection from this collection by removing all elements of another collection.

    Creates a new collection from this collection by removing all elements of another collection.

    xs

      the collection containing the removed elements.

    returns

      a new collection that contains all elements of the current collection except one less occurrence of each of the elements of `elems`.

    Definition Classes
      Subtractable
12.  def ->[B](y: B): (MapProxyLike[A, B, This], B)
    Implicit
      This member is added by an implicit conversion from MapProxyLike[A, B, This] to ArrowAssoc[MapProxyLike[A, B, This]] performed by method ArrowAssoc in scala.Predef.
    Definition Classes
      ArrowAssoc
    Annotations
      @inline()
13.  def /:[B](z: B)(op: (B, (A, B)) ⇒ B): B

    Applies a binary operator to a start value and all elements of this traversable collection, going left to right.

    Applies a binary operator to a start value and all elements of this traversable collection, going left to right.

    Note: `/:` is alternate syntax for `foldLeft`; `z /: xs` is the same as `xs foldLeft z`.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

        scala> val a = List(1,2,3,4)
        a: List[Int] = List(1, 2, 3, 4)

        scala> val b = (5 /: a)(_+_)
        b: Int = 15

        scala> val c = (5 /: a)((x,y) => x + y)
        c: Int = 15

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    z

      the start value.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this traversable collection, going left to right with the start value `z` on the left:

          op(...op(op(z, x_1), x_2), ..., x_n)

      where `x1, ..., xn` are the elements of this traversable collection.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
14.  def :\[B](z: B)(op: ((A, B), B) ⇒ B): B

    Applies a binary operator to all elements of this traversable collection and a start value, going right to left.

    Applies a binary operator to all elements of this traversable collection and a start value, going right to left.

    Note: `:\` is alternate syntax for `foldRight`; `xs :\ z` is the same as `xs foldRight z`.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    Examples:

    Note that the folding function used to compute b is equivalent to that used to compute c.

        scala> val a = List(1,2,3,4)
        a: List[Int] = List(1, 2, 3, 4)

        scala> val b = (a :\ 5)(_+_)
        b: Int = 15

        scala> val c = (a :\ 5)((x,y) => x + y)
        c: Int = 15

    B

      the result type of the binary operator.

    z

      the start value

    op

      the binary operator

    returns

      the result of inserting `op` between consecutive elements of this traversable collection, going right to left with the start value `z` on the right:

          op(x_1, op(x_2, ... op(x_n, z)...))

      where `x1, ..., xn` are the elements of this traversable collection.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
15.  final def ==(arg0: Any): Boolean

    The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

    The expression `x == that` is equivalent to `if (x eq null) that eq null else x.equals(that)`.

    returns

      `true` if the receiver object is equivalent to the argument; `false` otherwise.

    Definition Classes
      AnyRef → Any
16.  def addString(b: StringBuilder, start: String, sep: String, end: String): StringBuilder

    Appends all elements of this map to a string builder using start, end, and separator strings.

    Appends all elements of this map to a string builder using start, end, and separator strings. The written text begins with the string `start` and ends with the string `end`. Inside, the string representations (w.r.t. the method `toString`) of all elements of this map are separated by the string `sep`.

    Example:

        scala> val a = List(1,2,3,4)
        a: List[Int] = List(1, 2, 3, 4)

        scala> val b = new StringBuilder()
        b: StringBuilder =

        scala> a.addString(b , "List(" , ", " , ")")
        res5: StringBuilder = List(1, 2, 3, 4)

    b

      the string builder to which elements are appended.

    start

      the starting string.

    sep

      the separator string.

    end

      the ending string.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      MapProxyLike → TraversableProxyLike → MapLike → TraversableOnce
17.  def addString(b: mutable.StringBuilder): mutable.StringBuilder

    Appends all elements of this traversable collection to a string builder.

    Appends all elements of this traversable collection to a string builder. The written text consists of the string representations (w.r.t. the method `toString`) of all elements of this traversable collection without any separator string.

    Example:

        scala> val a = List(1,2,3,4)
        a: List[Int] = List(1, 2, 3, 4)

        scala> val b = new StringBuilder()
        b: StringBuilder =

        scala> val h = a.addString(b)
        h: StringBuilder = 1234

    b

      the string builder to which elements are appended.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      TraversableProxyLike → TraversableOnce
18.  def addString(b: mutable.StringBuilder, sep: String): mutable.StringBuilder

    Appends all elements of this traversable collection to a string builder using a separator string.

    Appends all elements of this traversable collection to a string builder using a separator string. The written text consists of the string representations (w.r.t. the method `toString`) of all elements of this traversable collection, separated by the string `sep`.

    Example:

        scala> val a = List(1,2,3,4)
        a: List[Int] = List(1, 2, 3, 4)

        scala> val b = new StringBuilder()
        b: StringBuilder =

        scala> a.addString(b, ", ")
        res0: StringBuilder = 1, 2, 3, 4

    b

      the string builder to which elements are appended.

    sep

      the separator string.

    returns

      the string builder `b` to which elements were appended.

    Definition Classes
      TraversableProxyLike → TraversableOnce
19.  def aggregate[B](z: ⇒ B)(seqop: (B, (A, B)) ⇒ B, combop: (B, B) ⇒ B): B

    Aggregates the results of applying an operator to subsequent elements.

    Aggregates the results of applying an operator to subsequent elements.

    This is a more general form of `fold` and `reduce`. It is similar to `foldLeft` in that it doesn't require the result to be a supertype of the element type. In addition, it allows parallel collections to be processed in chunks, and then combines the intermediate results.

    `aggregate` splits the traversable or iterator into partitions and processes each partition by sequentially applying `seqop`, starting with `z` (like `foldLeft`). Those intermediate results are then combined by using `combop` (like `fold`). The implementation of this operation may operate on an arbitrary number of collection partitions (even 1), so `combop` may be invoked an arbitrary number of times (even 0).

    As an example, consider summing up the integer values of a list of chars. The initial value for the sum is 0. First, `seqop` transforms each input character to an Int and adds it to the sum (of the partition). Then, `combop` just needs to sum up the intermediate results of the partitions:

        List('a', 'b', 'c').aggregate(0)({ (sum, ch) => sum + ch.toInt }, { (p1, p2) => p1 + p2 })

    B

      the type of accumulated results

    z

      the initial value for the accumulated result of the partition - this will typically be the neutral element for the `seqop` operator (e.g. `Nil` for list concatenation or `0` for summation) and may be evaluated more than once

    seqop

      an operator used to accumulate results within a partition

    combop

      an associative operator used to combine results from different partitions

    Definition Classes
      TraversableOnce → GenTraversableOnce
20.  def andThen[C](k: (B) ⇒ C): PartialFunction[A, C]

    Composes this partial function with a transformation function that gets applied to results of this partial function.

    Composes this partial function with a transformation function that gets applied to results of this partial function.

    C

      the result type of the transformation function.

    k

      the transformation function

    returns

      a partial function with the same domain as this partial function, which maps arguments `x` to `k(this(x))`.

    Definition Classes
      PartialFunction → Function1
21.  def apply(key: A): B

    Retrieves the value which is associated with the given key.

    Retrieves the value which is associated with the given key. This method invokes the `default` method of the map if there is no mapping from the given key to a value. Unless overridden, the `default` method throws a `NoSuchElementException`.

    key

      the key

    returns

      the value associated with the given key, or the result of the map's `default` method, if none exists.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike → Function1
22.  def applyOrElse[K1 <: A, V1 >: B](x: K1, default: (K1) ⇒ V1): V1

    Applies this partial function to the given argument when it is contained in the function domain.

    Applies this partial function to the given argument when it is contained in the function domain. Applies fallback function where this partial function is not defined.

    Note that expression `pf.applyOrElse(x, default)` is equivalent to

        if(pf isDefinedAt x) pf(x) else default(x)

    except that `applyOrElse` method can be implemented more efficiently. For all partial function literals the compiler generates an `applyOrElse` implementation which avoids double evaluation of pattern matchers and guards. This makes `applyOrElse` the basis for the efficient implementation for many operations and scenarios, such as:

    - combining partial functions into `orElse`/`andThen` chains does not lead to excessive `apply`/`isDefinedAt` evaluation
    - `lift` and `unlift` do not evaluate source functions twice on each invocation
    - `runWith` allows efficient imperative-style combining of partial functions with conditionally applied actions

    For non-literal partial function classes with nontrivial `isDefinedAt` method it is recommended to override `applyOrElse` with custom implementation that avoids double `isDefinedAt` evaluation. This may result in better performance and more predictable behavior w.r.t. side effects.

    x

      the function argument

    default

      the fallback function

    returns

      the result of this function or fallback function application.

    Definition Classes
      MapLike → PartialFunction
    Since

      2.10

23.  final def asInstanceOf[T0]: T0

    Cast the receiver object to be of type `T0`.

    Cast the receiver object to be of type `T0`.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression `1.asInstanceOf[String]` will throw a `ClassCastException` at runtime, while the expression `List(1).asInstanceOf[List[String]]` will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested type.

    returns

      the receiver object.

    Definition Classes
      Any
    Exceptions thrown

      `ClassCastException` if the receiver object is not an instance of the erasure of type `T0`.

24.  def canEqual(that: Any): Boolean

    Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

    Method called from equality methods, so that user-defined subclasses can refuse to be equal to other collections of the same kind.

    that

      The object with which this iterable collection should be compared

    returns

      `true`, if this iterable collection can possibly equal `that`, `false` otherwise. The test takes into consideration only the run-time types of objects but ignores their elements.

    Definition Classes
      IterableLike → Equals
25.  def clone(): AnyRef

    Create a copy of the receiver object.

    Create a copy of the receiver object.

    The default implementation of the `clone` method is platform dependent.

    returns

      a copy of the receiver object.

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
    Note

      not specified by SLS as a member of AnyRef

26.  def collect[B](pf: PartialFunction[A, B]): Map[B]

    [use case] Builds a new collection by applying a partial function to all elements of this map on which the function is defined.

    [use case]

    Builds a new collection by applying a partial function to all elements of this map on which the function is defined.

    B

      the element type of the returned collection.

    pf

      the partial function which filters and maps the map.

    returns

      a new map resulting from applying the given partial function `pf` to each element on which it is defined and collecting the results. The order of the elements is preserved.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
     Full Signature

    #### def collect[B, That](pf: PartialFunction[(A, B), B])(implicit bf: CanBuildFrom[This, B, That]): That

27.  def collectFirst[B](pf: PartialFunction[(A, B), B]): Option[B]

    Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.

    Finds the first element of the traversable or iterator for which the given partial function is defined, and applies the partial function to it.

    Note: may not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    pf

      the partial function

    returns

      an option value containing pf applied to the first value for which it is defined, or `None` if none exists.

    Definition Classes
      TraversableOnce
    Example:

    1. `Seq("a", 1, 5L).collectFirst({ case x: Int => x*10 }) = Some(10)`

28.  def compose[A](g: (A) ⇒ A): (A) ⇒ B

    Composes two instances of Function1 in a new Function1, with this function applied last.

    Composes two instances of Function1 in a new Function1, with this function applied last.

    A

      the type to which function `g` can be applied

    g

      a function A => T1

    returns

      a new function `f` such that `f(x) == apply(g(x))`

    Definition Classes
      Function1
    Annotations
      @unspecialized()
29.  def contains(key: A): Boolean

    Tests whether this map contains a binding for a key.

    Tests whether this map contains a binding for a key.

    key

      the key

    returns

      `true` if there is a binding for `key` in this map, `false` otherwise.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
30.  def copyToArray(xs: Array[A]): Unit

    [use case] Copies the elements of this map to an array.

    [use case]

    Copies the elements of this map to an array. Fills the given array `xs` with values of this map. Copying will stop once either the end of the current map is reached, or the end of the target array is reached.

    xs

      the array to fill.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
     Full Signature

    #### def copyToArray[B >: (A, B)](xs: Array[B]): Unit

31.  def copyToArray(xs: Array[A], start: Int): Unit

    [use case] Copies the elements of this map to an array.

    [use case]

    Copies the elements of this map to an array. Fills the given array `xs` with values of this map, beginning at index `start`. Copying will stop once either the end of the current map is reached, or the end of the target array is reached.

    xs

      the array to fill.

    start

      the starting index.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
     Full Signature

    #### def copyToArray[B >: (A, B)](xs: Array[B], start: Int): Unit

32.  def copyToArray(xs: Array[A], start: Int, len: Int): Unit

    [use case] Copies the elements of this map to an array.

    [use case]

    Copies the elements of this map to an array. Fills the given array `xs` with at most `len` elements of this map, starting at position `start`. Copying will stop once either the end of the current map is reached, or the end of the target array is reached, or `len` elements have been copied.

    xs

      the array to fill.

    start

      the starting index.

    len

      the maximal number of elements to copy.

    Definition Classes
      TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
     Full Signature

    #### def copyToArray[B >: (A, B)](xs: Array[B], start: Int, len: Int): Unit

33.  def copyToBuffer[B >: (A, B)](dest: Buffer[B]): Unit

    Copies all elements of this traversable collection to a buffer.

    Copies all elements of this traversable collection to a buffer.

    Note: will not terminate for infinite-sized collections.

    dest

      The buffer to which elements are copied.

    Definition Classes
      TraversableProxyLike → TraversableOnce
34.  def count(p: ((A, B)) ⇒ Boolean): Int

    Counts the number of elements in the traversable collection which satisfy a predicate.

    Counts the number of elements in the traversable collection which satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      the number of elements satisfying the predicate `p`.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
35.  def default(key: A): B

    Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.

    Defines the default value computation for the map, returned when a key is not found The method implemented here throws an exception, but it might be overridden in subclasses.

    key

      the given key value for which a binding is missing.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
    Exceptions thrown
36.  def drop(n: Int): This

    Selects all elements except first n ones.

    Selects all elements except first n ones.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

      the number of elements to drop from this traversable collection.

    returns

      a traversable collection consisting of all elements of this traversable collection except the first `n` ones, or else the empty traversable collection, if this traversable collection has less than `n` elements.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
37.  def dropRight(n: Int): This

    Selects all elements except last n ones.

    Selects all elements except last n ones.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    n

      The number of elements to take

    returns

      a iterable collection consisting of all elements of this iterable collection except the last `n` ones, or else the empty iterable collection, if this iterable collection has less than `n` elements.

    Definition Classes
      IterableProxyLike → IterableLike
38.  def dropWhile(p: ((A, B)) ⇒ Boolean): This

    Drops longest prefix of elements that satisfy a predicate.

    Drops longest prefix of elements that satisfy a predicate.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the longest suffix of this traversable collection whose first element does not satisfy the predicate `p`.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
39.  def ensuring(cond: (MapProxyLike[A, B, This]) ⇒ Boolean, msg: ⇒ Any): MapProxyLike[A, B, This]
    Implicit
      This member is added by an implicit conversion from MapProxyLike[A, B, This] to Ensuring[MapProxyLike[A, B, This]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
40.  def ensuring(cond: (MapProxyLike[A, B, This]) ⇒ Boolean): MapProxyLike[A, B, This]
    Implicit
      This member is added by an implicit conversion from MapProxyLike[A, B, This] to Ensuring[MapProxyLike[A, B, This]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
41.  def ensuring(cond: Boolean, msg: ⇒ Any): MapProxyLike[A, B, This]
    Implicit
      This member is added by an implicit conversion from MapProxyLike[A, B, This] to Ensuring[MapProxyLike[A, B, This]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
42.  def ensuring(cond: Boolean): MapProxyLike[A, B, This]
    Implicit
      This member is added by an implicit conversion from MapProxyLike[A, B, This] to Ensuring[MapProxyLike[A, B, This]] performed by method Ensuring in scala.Predef.
    Definition Classes
      Ensuring
43.  final def eq(arg0: AnyRef): Boolean

    Tests whether the argument (`that`) is a reference to the receiver object (`this`).

    Tests whether the argument (`that`) is a reference to the receiver object (`this`).

    The `eq` method implements an equivalence relation on non-null instances of `AnyRef`, and has three additional properties:

    - It is consistent: for any non-null instances `x` and `y` of type `AnyRef`, multiple invocations of `x.eq(y)` consistently returns `true` or consistently returns `false`.
    - For any non-null instance `x` of type `AnyRef`, `x.eq(null)` and `null.eq(x)` returns `false`.
    - `null.eq(null)` returns `true`.

    When overriding the `equals` or `hashCode` methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (`o1 eq o2`), they should be equal to each other (`o1 == o2`) and they should hash to the same value (`o1.hashCode == o2.hashCode`).

    returns

      `true` if the argument is a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef
44.  def equals(that: Any): Boolean

    Compares the receiver object (`this`) with the argument object (`that`) for equivalence.

    Compares the receiver object (`this`) with the argument object (`that`) for equivalence.

    Any implementation of this method should be an equivalence relation:

    - It is reflexive: for any instance `x` of type `Any`, `x.equals(x)` should return `true`.
    - It is symmetric: for any instances `x` and `y` of type `Any`, `x.equals(y)` should return `true` if and only if `y.equals(x)` returns `true`.
    - It is transitive: for any instances `x`, `y`, and `z` of type `Any` if `x.equals(y)` returns `true` and `y.equals(z)` returns `true`, then `x.equals(z)` should return `true`.

    If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is usually necessary to override `hashCode` to ensure that objects which are "equal" (`o1.equals(o2)` returns `true`) hash to the same scala.Int. (`o1.hashCode.equals(o2.hashCode)`).

    that

      the object to compare against this object for equality.

    returns

      `true` if the receiver object is equivalent to the argument; `false` otherwise.

    Definition Classes
      Proxy → Any
45.  def exists(p: ((A, B)) ⇒ Boolean): Boolean

    Tests whether a predicate holds for at least one element of this traversable collection.

    Tests whether a predicate holds for at least one element of this traversable collection.

    Note: may not terminate for infinite-sized collections.

    p

      the predicate used to test elements.

    returns

      `false` if this traversable collection is empty, otherwise `true` if the given predicate `p` holds for some of the elements of this traversable collection, otherwise `false`

    Definition Classes
      TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
46.  def filter(p: ((A, B)) ⇒ Boolean): This

    Selects all elements of this traversable collection which satisfy a predicate.

    Selects all elements of this traversable collection which satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      a new traversable collection consisting of all elements of this traversable collection that satisfy the given predicate `p`. The order of the elements is preserved.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
47.  def filterKeys(p: (A) ⇒ Boolean): Map[A, B]

    Filters this map by retaining only keys satisfying a predicate.

    Filters this map by retaining only keys satisfying a predicate.

    Note: the predicate must accept any key of type `K`, not just those already present in the map, as the predicate is tested before the underlying map is queried.

    p

      the predicate used to test keys

    returns

      an immutable map consisting only of those key value pairs of this map where the key satisfies the predicate `p`. The resulting map wraps the original map without copying any elements.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
48.  def filterNot(p: ((A, B)) ⇒ Boolean): This

    Selects all elements of this map which do not satisfy a predicate.

    Selects all elements of this map which do not satisfy a predicate.

    p

      the predicate used to test elements.

    returns

      a new map consisting of all elements of this map that do not satisfy the given predicate `p`. The order of the elements is preserved.

    Definition Classes
      MapProxyLike → TraversableProxyLike → MapLike → TraversableLike → GenTraversableLike
49.  def finalize(): Unit

    Called by the garbage collector on the receiver object when there are no more references to the object.

    Called by the garbage collector on the receiver object when there are no more references to the object.

    The details of when and if the `finalize` method is invoked, as well as the interaction between `finalize` and non-local returns and exceptions, are all platform dependent.

    Attributes
      protected[java.lang]
    Definition Classes
      AnyRef
    Annotations
      @throws( classOf[java.lang.Throwable] )
    Note

      not specified by SLS as a member of AnyRef

50.  def find(p: ((A, B)) ⇒ Boolean): Option[(A, B)]

    Finds the first element of the traversable collection satisfying a predicate, if any.

    Finds the first element of the traversable collection satisfying a predicate, if any.

    Note: may not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    p

      the predicate used to test elements.

    returns

      an option value containing the first element in the traversable collection that satisfies `p`, or `None` if none exists.

    Definition Classes
      TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
51.  def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): Map[B]

    [use case] Builds a new collection by applying a function to all elements of this map and using the elements of the resulting collections.

    [use case]

    Builds a new collection by applying a function to all elements of this map and using the elements of the resulting collections.

    For example:

        def getWords(lines: Seq[String]): Seq[String] = lines flatMap (line => line split "\\W+")

    The type of the resulting collection is guided by the static type of map. This might cause unexpected results sometimes. For example:

        // lettersOf will return a Seq[Char] of likely repeated letters, instead of a Set
        def lettersOf(words: Seq[String]) = words flatMap (word => word.toSet)

        // lettersOf will return a Set[Char], not a Seq
        def lettersOf(words: Seq[String]) = words.toSet flatMap (word => word.toSeq)

        // xs will be an Iterable[Int]
        val xs = Map("a" -> List(11,111), "b" -> List(22,222)).flatMap(_._2)

        // ys will be a Map[Int, Int]
        val ys = Map("a" -> List(1 -> 11,1 -> 111), "b" -> List(2 -> 22,2 -> 222)).flatMap(_._2)

    B

      the element type of the returned collection.

    f

      the function to apply to each element.

    returns

      a new map resulting from applying the given collection-valued function `f` to each element of this map and concatenating the results.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike → FilterMonadic
     Full Signature

    #### def flatMap[B, That](f: ((A, B)) ⇒ GenTraversableOnce[B])(implicit bf: CanBuildFrom[This, B, That]): That

52.  def fold[A1 >: (A, B)](z: A1)(op: (A1, A1) ⇒ A1): A1

    Folds the elements of this traversable or iterator using the specified associative binary operator.

    Folds the elements of this traversable or iterator using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    Note: will not terminate for infinite-sized collections.

    A1

      a type parameter for the binary operator, a supertype of `A`.

    z

      a neutral element for the fold operation; may be added to the result an arbitrary number of times, and must not change the result (e.g., `Nil` for list concatenation, 0 for addition, or 1 for multiplication).

    op

      a binary operator that must be associative.

    returns

      the result of applying the fold operator `op` between all the elements and `z`, or `z` if this traversable or iterator is empty.

    Definition Classes
      TraversableOnce → GenTraversableOnce
53.  def foldLeft[B](z: B)(op: (B, (A, B)) ⇒ B): B

    Applies a binary operator to a start value and all elements of this traversable collection, going left to right.

    Applies a binary operator to a start value and all elements of this traversable collection, going left to right.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    z

      the start value.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this traversable collection, going left to right with the start value `z` on the left:

          op(...op(z, x_1), x_2, ..., x_n)

      where `x1, ..., xn` are the elements of this traversable collection. Returns `z` if this traversable collection is empty.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
54.  def foldRight[B](z: B)(op: ((A, B), B) ⇒ B): B

    Applies a binary operator to all elements of this traversable collection and a start value, going right to left.

    Applies a binary operator to all elements of this traversable collection and a start value, going right to left.

    Note: will not terminate for infinite-sized collections.

    Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

    B

      the result type of the binary operator.

    z

      the start value.

    op

      the binary operator.

    returns

      the result of inserting `op` between consecutive elements of this traversable collection, going right to left with the start value `z` on the right:

          op(x_1, op(x_2, ... op(x_n, z)...))

      where `x1, ..., xn` are the elements of this traversable collection. Returns `z` if this traversable collection is empty.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
55.  def forall(p: ((A, B)) ⇒ Boolean): Boolean

    Tests whether a predicate holds for all elements of this traversable collection.

    Tests whether a predicate holds for all elements of this traversable collection.

    Note: may not terminate for infinite-sized collections.

    p

      the predicate used to test elements.

    returns

      `true` if this traversable collection is empty or the given predicate `p` holds for all elements of this traversable collection, otherwise `false`.

    Definition Classes
      TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
56.  def foreach(f: (A) ⇒ Unit): Unit

    [use case] Applies a function `f` to all elements of this map.

    [use case]

    Applies a function `f` to all elements of this map.

    Note: this method underlies the implementation of most other bulk operations. It's important to implement this method in an efficient way.

    f

      the function that is applied for its side-effect to every element. The result of function `f` is discarded.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike → TraversableOnce → GenTraversableOnce → FilterMonadic
     Full Signature

    #### def foreach[U](f: ((A, B)) ⇒ U): Unit

57.  def formatted(fmtstr: String): String

    Returns string formatted according to given `format` string.

    Returns string formatted according to given `format` string. Format strings are as for `String.format` (@see java.lang.String.format).

    Implicit
      This member is added by an implicit conversion from MapProxyLike[A, B, This] to StringFormat[MapProxyLike[A, B, This]] performed by method StringFormat in scala.Predef.
    Definition Classes
      StringFormat
    Annotations
      @inline()
58.  def get(key: A): Option[B]

    Optionally returns the value associated with a key.

    Optionally returns the value associated with a key.

    key

      the key value

    returns

      an option value containing the value associated with `key` in this map, or `None` if none exists.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
59.  final def getClass(): Class[_]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

      a class object corresponding to the runtime type of the receiver.

    Definition Classes
      AnyRef → Any
60.  def getOrElse(key: K, default: ⇒ V): V

    [use case] Returns the value associated with a key, or a default value if the key is not contained in the map.

    [use case]

    Returns the value associated with a key, or a default value if the key is not contained in the map.

    key

      the key.

    default

      a computation that yields a default value in case no binding for `key` is found in the map.

    returns

      the value associated with `key` if it exists, otherwise the result of the `default` computation.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
     Full Signature

    #### def getOrElse[B1 >: B](key: A, default: ⇒ B1): B1

61.  def groupBy[K](f: ((A, B)) ⇒ K): immutable.Map[K, This]

    Partitions this traversable collection into a map of traversable collections according to some discriminator function.

    Partitions this traversable collection into a map of traversable collections according to some discriminator function.

    Note: this method is not re-implemented by views. This means when applied to a view it will always force the view and return a new traversable collection.

    K

      the type of keys returned by the discriminator function.

    f

      the discriminator function.

    returns

      A map from keys to traversable collections such that the following invariant holds:

          (xs groupBy f)(k) = xs filter (x => f(x) == k)

      That is, every key `k` is bound to a traversable collection of those elements `x` for which `f(x)` equals `k`.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
62.  def grouped(size: Int): Iterator[This]

    Partitions elements in fixed size iterable collections.

    Partitions elements in fixed size iterable collections.

    size

      the number of elements per group

    returns

      An iterator producing iterable collections of size `size`, except the last will be less than size `size` if the elements don't divide evenly.

    Definition Classes
      IterableProxyLike → IterableLike
    See also

      scala.collection.Iterator, method `grouped`

63.  def hasDefiniteSize: Boolean

    Tests whether this traversable collection is known to have a finite size.

    Tests whether this traversable collection is known to have a finite size. All strict collections are known to have finite size. For a non-strict collection such as `Stream`, the predicate returns `true` if all elements have been computed. It returns `false` if the stream is not yet evaluated to the end. Non-empty Iterators usually return `false` even if they were created from a collection with a known finite size.

    Note: many collection methods will not work on collections of infinite sizes. The typical failure mode is an infinite loop. These methods always attempt a traversal without checking first that `hasDefiniteSize` returns `true`. However, checking `hasDefiniteSize` can provide an assurance that size is well-defined and non-termination is not a concern.

    returns

      `true` if this collection is known to have finite size, `false` otherwise.

    Definition Classes
      TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
64.  def hashCode(): Int

    Calculate a hash code value for the object.

    Calculate a hash code value for the object.

    The default hashing algorithm is platform dependent.

    Note that it is allowed for two objects to have identical hash codes (`o1.hashCode.equals(o2.hashCode)`) yet not be equal (`o1.equals(o2)` returns `false`). A degenerate implementation could always return `0`. However, it is required that if two objects are equal (`o1.equals(o2)` returns `true`) that they have identical hash codes (`o1.hashCode.equals(o2.hashCode)`). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the `equals` method.

    returns

      the hash code value for this object.

    Definition Classes
      Proxy → Any
65.  def head: (A, B)

    Selects the first element of this traversable collection.

    Selects the first element of this traversable collection.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the first element of this traversable collection.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
    Exceptions thrown

      `NoSuchElementException` if the traversable collection is empty.

66.  def headOption: Option[(A, B)]

    Optionally selects the first element.

    Optionally selects the first element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the first element of this traversable collection if it is nonempty, `None` if it is empty.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
67.  def init: This

    Selects all elements except the last.

    Selects all elements except the last.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      a traversable collection consisting of all elements of this traversable collection except the last one.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
    Exceptions thrown

      `UnsupportedOperationException` if the traversable collection is empty.

68.  def inits: Iterator[This]

    Iterates over the inits of this traversable collection.

    Iterates over the inits of this traversable collection. The first value will be this traversable collection and the final one will be an empty traversable collection, with the intervening values the results of successive applications of `init`.

    returns

      an iterator over all the inits of this traversable collection

    Definition Classes
      TraversableLike
    Example:

    1. `List(1,2,3).inits = Iterator(List(1,2,3), List(1,2), List(1), Nil)`

69.  def isDefinedAt(key: A): Boolean

    Tests whether this map contains a binding for a key.

    Tests whether this map contains a binding for a key. This method, which implements an abstract method of trait `PartialFunction`, is equivalent to `contains`.

    key

      the key

    returns

      `true` if there is a binding for `key` in this map, `false` otherwise.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike → PartialFunction
70.  def isEmpty: Boolean

    Tests whether this map is empty.

    Tests whether this map is empty.

    returns

      `true` if the map contain no elements, `false` otherwise.

    Definition Classes
      MapProxyLike → TraversableProxyLike → MapLike → IterableLike → TraversableLike → TraversableOnce → GenTraversableOnce
71.  final def isInstanceOf[T0]: Boolean

    Test whether the dynamic type of the receiver object is `T0`.

    Test whether the dynamic type of the receiver object is `T0`.

    Note that the result of the test is modulo Scala's erasure semantics. Therefore the expression `1.isInstanceOf[String]` will return `false`, while the expression `List(1).isInstanceOf[List[String]]` will return `true`. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the specified type.

    returns

      `true` if the receiver object is an instance of erasure of type `T0`; `false` otherwise.

    Definition Classes
      Any
72.  final def isTraversableAgain: Boolean

    Tests whether this traversable collection can be repeatedly traversed.

    Tests whether this traversable collection can be repeatedly traversed.

    returns

      `true`

    Definition Classes
      TraversableLike → GenTraversableLike → GenTraversableOnce
73.  def iterator: Iterator[(A, B)]

    Creates a new iterator over all elements contained in this iterable object.

    Creates a new iterator over all elements contained in this iterable object.

    returns

      the new iterator

    Definition Classes
      MapProxyLike → IterableProxyLike → MapLike → IterableLike → GenIterableLike
74.  def keySet: Set[A]

    Collects all keys of this map in a set.

    Collects all keys of this map in a set.

    returns

      a set containing all keys of this map.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
75.  def keys: Iterable[A]

    Collects all keys of this map in an iterable collection.

    Collects all keys of this map in an iterable collection.

    returns

      the keys of this map as an iterable.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
76.  def keysIterator: Iterator[A]

    Creates an iterator for all keys.

    Creates an iterator for all keys.

    returns

      an iterator over all keys.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
77.  def last: (A, B)

    Selects the last element.

    Selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      The last element of this traversable collection.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
    Exceptions thrown

      `NoSuchElementException` If the traversable collection is empty.

78.  def lastOption: Option[(A, B)]

    Optionally selects the last element.

    Optionally selects the last element.

    Note: might return different results for different runs, unless the underlying collection type is ordered.

    returns

      the last element of this traversable collection$ if it is nonempty, `None` if it is empty.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
79.  def lift: (A) ⇒ Option[B]

    Turns this partial function into a plain function returning an `Option` result.

    Turns this partial function into a plain function returning an `Option` result.

    returns

      a function that takes an argument `x` to `Some(this(x))` if `this` is defined for `x`, and to `None` otherwise.

    Definition Classes
      PartialFunction
    See also

      Function.unlift

80.  def map[B](f: (A) ⇒ B): Map[B]

    [use case] Builds a new collection by applying a function to all elements of this map.

    [use case]

    Builds a new collection by applying a function to all elements of this map.

    B

      the element type of the returned collection.

    f

      the function to apply to each element.

    returns

      a new map resulting from applying the given function `f` to each element of this map and collecting the results.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike → FilterMonadic
     Full Signature

    #### def map[B, That](f: ((A, B)) ⇒ B)(implicit bf: CanBuildFrom[This, B, That]): That

81.  def mapValues[C](f: (B) ⇒ C): Map[A, C]

    Transforms this map by applying a function to every retrieved value.

    Transforms this map by applying a function to every retrieved value.

    f

      the function used to transform values of this map.

    returns

      a map view which maps every key of this map to `f(this(key))`. The resulting map wraps the original map without copying any elements.

    Definition Classes
      MapProxyLike → MapLike → GenMapLike
82.  def max: A

    [use case] Finds the largest element.

    [use case]

    Finds the largest element.

    returns

      the largest element of this map.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
     Full Signature

    #### def max[B >: (A, B)](implicit cmp: Ordering[B]): (A, B)

83.  def maxBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the largest value measured by function f.

    [use case]

    Finds the first element which yields the largest value measured by function f.

    B

      The result type of the function f.

    f

      The measuring function.

    returns

      the first element of this map with the largest value measured by function f.

    Definition Classes
      TraversableOnce → GenTraversableOnce
     Full Signature

    #### def maxBy[B](f: ((A, B)) ⇒ B)(implicit cmp: Ordering[B]): (A, B)

84.  def min: A

    [use case] Finds the smallest element.

    [use case]

    Finds the smallest element.

    returns

      the smallest element of this map

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
     Full Signature

    #### def min[B >: (A, B)](implicit cmp: Ordering[B]): (A, B)

85.  def minBy[B](f: (A) ⇒ B): A

    [use case] Finds the first element which yields the smallest value measured by function f.

    [use case]

    Finds the first element which yields the smallest value measured by function f.

    B

      The result type of the function f.

    f

      The measuring function.

    returns

      the first element of this map with the smallest value measured by function f.

    Definition Classes
      TraversableOnce → GenTraversableOnce
     Full Signature

    #### def minBy[B](f: ((A, B)) ⇒ B)(implicit cmp: Ordering[B]): (A, B)

86.  def mkString: String

    Displays all elements of this traversable collection in a string.

    Displays all elements of this traversable collection in a string.

    returns

      a string representation of this traversable collection. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this traversable collection follow each other without any separator string.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
87.  def mkString(sep: String): String

    Displays all elements of this traversable collection in a string using a separator string.

    Displays all elements of this traversable collection in a string using a separator string.

    sep

      the separator string.

    returns

      a string representation of this traversable collection. In the resulting string the string representations (w.r.t. the method `toString`) of all elements of this traversable collection are separated by the string `sep`.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
    Example:

    1. `List(1, 2, 3).mkString("|") = "1|2|3"`

88.  def mkString(start: String, sep: String, end: String): String

    Displays all elements of this traversable collection in a string using start, end, and separator strings.

    Displays all elements of this traversable collection in a string using start, end, and separator strings.

    start

      the starting string.

    sep

      the separator string.

    end

      the ending string.

    returns

      a string representation of this traversable collection. The resulting string begins with the string `start` and ends with the string `end`. Inside, the string representations (w.r.t. the method `toString`) of all elements of this traversable collection are separated by the string `sep`.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
    Example:

    1. `List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"`

89.  final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

      `true` if the argument is not a reference to the receiver object; `false` otherwise.

    Definition Classes
      AnyRef
90.  def newBuilder: Builder[(A, B), This]

    A common implementation of `newBuilder` for all maps in terms of `empty`.

    A common implementation of `newBuilder` for all maps in terms of `empty`. Overridden for mutable maps in `mutable.MapLike`.

    Attributes
      protected[this]
    Definition Classes
      MapLike → TraversableLike → HasNewBuilder
91.  def nonEmpty: Boolean

    Tests whether the traversable collection is not empty.

    Tests whether the traversable collection is not empty.

    returns

      `true` if the traversable collection contains at least one element, `false` otherwise.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
92.  final def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

93.  final def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    Definition Classes
      AnyRef
    Note

      not specified by SLS as a member of AnyRef

94.  def orElse[A1 <: A, B1 >: B](that: PartialFunction[A1, B1]): PartialFunction[A1, B1]

    Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

    Composes this partial function with a fallback partial function which gets applied where this partial function is not defined.

    A1

      the argument type of the fallback function

    B1

      the result type of the fallback function

    that

      the fallback function

    returns

      a partial function which has as domain the union of the domains of this partial function and `that`. The resulting partial function takes `x` to `this(x)` where `this` is defined, and to `that(x)` where it is not.

    Definition Classes
      PartialFunction
95.  def par: ParMap[A, B]

    Returns a parallel implementation of this collection.

    Returns a parallel implementation of this collection.

    For most collection types, this method creates a new parallel collection by copying all the elements. For these collection, `par` takes linear time. Mutable collections in this category do not produce a mutable parallel collection that has the same underlying dataset, so changes in one collection will not be reflected in the other one.

    Specific collections (e.g. `ParArray` or `mutable.ParHashMap`) override this default behaviour by creating a parallel collection which shares the same underlying dataset. For these collections, `par` takes constant or sublinear time.

    All parallel collections return a reference to themselves.

    returns

      a parallel implementation of this collection

    Definition Classes
      Parallelizable
96.  def parCombiner: Combiner[(A, B), ParMap[A, B]]

    The default `par` implementation uses the combiner provided by this method to create a new parallel collection.

    The default `par` implementation uses the combiner provided by this method to create a new parallel collection.

    returns

      a combiner for the parallel collection of type `ParRepr`

    Attributes
      protected[this]
    Definition Classes
      MapLike → TraversableLike → Parallelizable
97.  def partition(p: ((A, B)) ⇒ Boolean): (This, This)

    Partitions this traversable collection in two traversable collections according to a predicate.

    Partitions this traversable collection in two traversable collections according to a predicate.

    p

      the predicate on which to partition.

    returns

      a pair of traversable collections: the first traversable collection consists of all elements that satisfy the predicate `p` and the second traversable collection consists of all elements that don't. The relative order of the elements in the resulting traversable collections is the same as in the original traversable collection.

    Definition Classes
      TraversableProxyLike → TraversableLike → GenTraversableLike
98.  def product: A

    [use case] Multiplies up the elements of this collection.

    [use case]

    Multiplies up the elements of this collection.

    returns

      the product of all elements in this map of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the map and as result type of `product`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

    Definition Classes
      TraversableProxyLike → TraversableOnce → GenTraversableOnce
     Full Signature

    #### def product[B >: (A, B)](implicit num: Numeric[B]): B

99.  def reduce[A1 >: (A, B)](op: (A1, A1) ⇒ A1): A1

    Reduces the elements of this traversable or iterator using the specified associative binary operator.

    Reduces the elements of this traversable or iterator using the specified associative binary operator.

    The order in which operations are performed on elements is unspecified and may be nondeterministic.

    A1

      A type parameter for the binary operator, a supertype of `A`.

    op

      A binary operator that must be associative.

    returns

      The result of applying reduce operator `op` between all the elements if the traversable or iterator is nonempty.

    Definition Classes
      TraversableOnce → GenTraversableOnce
    Exceptions thrown

      `UnsupportedOperationException` if this traversable or iterator is empty.

100.  def reduceLeft[B >: (A, B)](op: (B, (A, B)) ⇒ B): B

     Applies a binary operator to all elements of this traversable collection, going left to right.

     Applies a binary operator to all elements of this traversable collection, going left to right.

     Note: will not terminate for infinite-sized collections.

     Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

     B

       the result type of the binary operator.

     op

       the binary operator.

     returns

       the result of inserting `op` between consecutive elements of this traversable collection, going left to right:

           op( op( ... op(x_1, x_2) ..., x_{n-1}), x_n)

       where `x1, ..., xn` are the elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce
     Exceptions thrown

       `UnsupportedOperationException` if this traversable collection is empty.

101.  def reduceLeftOption[B >: (A, B)](op: (B, (A, B)) ⇒ B): Option[B]

     Optionally applies a binary operator to all elements of this traversable collection, going left to right.

     Optionally applies a binary operator to all elements of this traversable collection, going left to right.

     Note: will not terminate for infinite-sized collections.

     Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

     B

       the result type of the binary operator.

     op

       the binary operator.

     returns

       an option value containing the result of `reduceLeft(op)` if this traversable collection is nonempty, `None` otherwise.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
102.  def reduceOption[A1 >: (A, B)](op: (A1, A1) ⇒ A1): Option[A1]

     Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.

     Reduces the elements of this traversable or iterator, if any, using the specified associative binary operator.

     The order in which operations are performed on elements is unspecified and may be nondeterministic.

     A1

       A type parameter for the binary operator, a supertype of `A`.

     op

       A binary operator that must be associative.

     returns

       An option value containing result of applying reduce operator `op` between all the elements if the collection is nonempty, and `None` otherwise.

     Definition Classes
       TraversableOnce → GenTraversableOnce
103.  def reduceRight[B >: (A, B)](op: ((A, B), B) ⇒ B): B

     Applies a binary operator to all elements of this traversable collection, going right to left.

     Applies a binary operator to all elements of this traversable collection, going right to left.

     Note: will not terminate for infinite-sized collections.

     Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

     B

       the result type of the binary operator.

     op

       the binary operator.

     returns

       the result of inserting `op` between consecutive elements of this traversable collection, going right to left:

           op(x_1, op(x_2, ..., op(x_{n-1}, x_n)...))

       where `x1, ..., xn` are the elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
     Exceptions thrown

       `UnsupportedOperationException` if this traversable collection is empty.

104.  def reduceRightOption[B >: (A, B)](op: ((A, B), B) ⇒ B): Option[B]

     Optionally applies a binary operator to all elements of this traversable collection, going right to left.

     Optionally applies a binary operator to all elements of this traversable collection, going right to left.

     Note: will not terminate for infinite-sized collections.

     Note: might return different results for different runs, unless the underlying collection type is ordered. or the operator is associative and commutative.

     B

       the result type of the binary operator.

     op

       the binary operator.

     returns

       an option value containing the result of `reduceRight(op)` if this traversable collection is nonempty, `None` otherwise.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
105.  def repr: This

     The collection of type traversable collection underlying this `TraversableLike` object.

     The collection of type traversable collection underlying this `TraversableLike` object. By default this is implemented as the `TraversableLike` object itself, but this can be overridden.

     Definition Classes
       TraversableLike → GenTraversableLike
106.  def reversed: List[(A, B)]
     Attributes
       protected[this]
     Definition Classes
       TraversableOnce
107.  def runWith[U](action: (B) ⇒ U): (A) ⇒ Boolean

     Composes this partial function with an action function which gets applied to results of this partial function.

     Composes this partial function with an action function which gets applied to results of this partial function. The action function is invoked only for its side effects; its result is ignored.

     Note that expression `pf.runWith(action)(x)` is equivalent to

         if(pf isDefinedAt x) { action(pf(x)); true } else false

     except that `runWith` is implemented via `applyOrElse` and thus potentially more efficient. Using `runWith` avoids double evaluation of pattern matchers and guards for partial function literals.

     action

       the action function

     returns

       a function which maps arguments `x` to `isDefinedAt(x)`. The resulting function runs `action(this(x))` where `this` is defined.

     Definition Classes
       PartialFunction
     Since

       2.10

     See also

       `applyOrElse`.

108.  def sameElements(that: GenIterable[A]): Boolean

     [use case] Checks if the other iterable collection contains the same elements in the same order as this map.

     [use case]

     Checks if the other iterable collection contains the same elements in the same order as this map.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     that

       the collection to compare with.

     returns

       `true`, if both collections contain the same elements in the same order, `false` otherwise.

     Definition Classes
       IterableProxyLike → IterableLike → GenIterableLike
      Full Signature

     #### def sameElements[B >: (A, B)](that: GenIterable[B]): Boolean

109.  def scan[B >: (A, B), That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[This, B, That]): That

     Computes a prefix scan of the elements of the collection.

     Computes a prefix scan of the elements of the collection.

     Note: The neutral element `z` may be applied more than once.

     B

       element type of the resulting collection

     That

       type of the resulting collection

     z

       neutral element for the operator `op`

     op

       the associative operator for the scan

     cbf

       combiner factory which provides a combiner

     returns

       a new traversable collection containing the prefix scan of the elements in this traversable collection

     Definition Classes
       TraversableLike → GenTraversableLike
110.  def scanLeft[B, That](z: B)(op: (B, (A, B)) ⇒ B)(implicit bf: CanBuildFrom[This, B, That]): That

     Produces a collection containing cumulative results of applying the operator going left to right.

     Produces a collection containing cumulative results of applying the operator going left to right.

     Note: will not terminate for infinite-sized collections.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     B

       the type of the elements in the resulting collection

     That

       the actual type of the resulting collection

     z

       the initial value

     op

       the binary operator applied to the intermediate result and the element

     bf

       an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and the new element type `B`.

     returns

       collection with intermediate results

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
111.  def scanRight[B, That](z: B)(op: ((A, B), B) ⇒ B)(implicit bf: CanBuildFrom[This, B, That]): That

     Produces a collection containing cumulative results of applying the operator going right to left.

     Produces a collection containing cumulative results of applying the operator going right to left. The head of the collection is the last cumulative result.

     Note: will not terminate for infinite-sized collections.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     Example:

         List(1, 2, 3, 4).scanRight(0)(_ + _) == List(10, 9, 7, 4, 0)

     B

       the type of the elements in the resulting collection

     That

       the actual type of the resulting collection

     z

       the initial value

     op

       the binary operator applied to the intermediate result and the element

     bf

       an implicit value of class `CanBuildFrom` which determines the result class `That` from the current representation type `Repr` and the new element type `B`.

     returns

       collection with intermediate results

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
112.  def size: Int

     The size of this traversable collection.

     The size of this traversable collection.

     Note: will not terminate for infinite-sized collections.

     returns

       the number of elements in this traversable collection.

     Definition Classes
       TraversableProxyLike → GenTraversableLike → TraversableOnce → GenTraversableOnce
113.  def sizeHintIfCheap: Int

     The size of this collection or iterator, if it can be cheaply computed

     The size of this collection or iterator, if it can be cheaply computed

     returns

       the number of elements in this collection or iterator, or -1 if the size cannot be determined cheaply

     Attributes
       protected[scala.collection]
     Definition Classes
       GenTraversableOnce
114.  def slice(from: Int, until: Int): This

     Selects an interval of elements.

     Selects an interval of elements. The returned collection is made up of all elements `x` which satisfy the invariant:

         from <= indexOf(x) < until

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     returns

       a traversable collection containing the elements greater than or equal to index `from` extending up to (but not including) index `until` of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
115.  def sliding(size: Int, step: Int): Iterator[This]

     Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

     Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in grouped.)

     size

       the number of elements per group

     step

       the distance between the first elements of successive groups

     returns

       An iterator producing iterable collections of size `size`, except the last element (which may be the only element) will be truncated if there are fewer than `size` elements remaining to be grouped.

     Definition Classes
       IterableProxyLike → IterableLike
     See also

       scala.collection.Iterator, method `sliding`

116.  def sliding(size: Int): Iterator[This]

     Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in `grouped`.) The "sliding window" step is set to one.

     Groups elements in fixed size blocks by passing a "sliding window" over them (as opposed to partitioning them, as is done in `grouped`.) The "sliding window" step is set to one.

     size

       the number of elements per group

     returns

       An iterator producing iterable collections of size `size`, except the last element (which may be the only element) will be truncated if there are fewer than `size` elements remaining to be grouped.

     Definition Classes
       IterableProxyLike → IterableLike
     See also

       scala.collection.Iterator, method `sliding`

117.  def span(p: ((A, B)) ⇒ Boolean): (This, This)

     Splits this traversable collection into a prefix/suffix pair according to a predicate.

     Splits this traversable collection into a prefix/suffix pair according to a predicate.

     Note: `c span p` is equivalent to (but possibly more efficient than) `(c takeWhile p, c dropWhile p)`, provided the evaluation of the predicate `p` does not cause any side-effects.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     returns

       a pair consisting of the longest prefix of this traversable collection whose elements all satisfy `p`, and the rest of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
118.  def splitAt(n: Int): (This, This)

     Splits this traversable collection into two at a given position.

     Splits this traversable collection into two at a given position. Note: `c splitAt n` is equivalent to (but possibly more efficient than) `(c take n, c drop n)`.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     n

       the position at which to split.

     returns

       a pair of traversable collections consisting of the first `n` elements of this traversable collection, and the other elements.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
119.  def stringPrefix: String

     Defines the prefix of this object's `toString` representation.

     Defines the prefix of this object's `toString` representation.

     returns

       a string representation which starts the result of `toString` applied to this traversable collection. By default the string prefix is the simple name of the collection class traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
120.  def sum: A

     [use case] Sums up the elements of this collection.

     [use case]

     Sums up the elements of this collection.

     returns

       the sum of all elements in this map of numbers of type `Int`. Instead of `Int`, any other type `T` with an implicit `Numeric[T]` implementation can be used as element type of the map and as result type of `sum`. Examples of such types are: `Long`, `Float`, `Double`, `BigInt`.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
      Full Signature

     #### def sum[B >: (A, B)](implicit num: Numeric[B]): B

121.  final def synchronized[T0](arg0: ⇒ T0): T0
     Definition Classes
       AnyRef
122.  def tail: This

     Selects all elements except the first.

     Selects all elements except the first.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     returns

       a traversable collection consisting of all elements of this traversable collection except the first one.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
     Exceptions thrown

       ``UnsupportedOperationException`` if the traversable collection is empty.

123.  def tails: Iterator[This]

     Iterates over the tails of this traversable collection.

     Iterates over the tails of this traversable collection. The first value will be this traversable collection and the final one will be an empty traversable collection, with the intervening values the results of successive applications of `tail`.

     returns

       an iterator over all the tails of this traversable collection

     Definition Classes
       TraversableLike
     Example:

     1. `List(1,2,3).tails = Iterator(List(1,2,3), List(2,3), List(3), Nil)`

124.  def take(n: Int): This

     Selects first n elements.

     Selects first n elements.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     n

       the number of elements to take from this traversable collection.

     returns

       a traversable collection consisting only of the first `n` elements of this traversable collection, or else the whole traversable collection, if it has less than `n` elements.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
125.  def takeRight(n: Int): This

     Selects last n elements.

     Selects last n elements.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     n

       the number of elements to take

     returns

       a iterable collection consisting only of the last `n` elements of this iterable collection, or else the whole iterable collection, if it has less than `n` elements.

     Definition Classes
       IterableProxyLike → IterableLike
126.  def takeWhile(p: ((A, B)) ⇒ Boolean): This

     Takes longest prefix of elements that satisfy a predicate.

     Takes longest prefix of elements that satisfy a predicate.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     returns

       the longest prefix of this traversable collection whose elements all satisfy the predicate `p`.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableLike
127.  def thisCollection: Iterable[(A, B)]

     The underlying collection seen as an instance of `Iterable`.

     The underlying collection seen as an instance of `Iterable`. By default this is implemented as the current collection object itself, but this can be overridden.

     Attributes
       protected[this]
     Definition Classes
       IterableLike → TraversableLike
128.  def to[Col[_]]: Col[A]

     [use case] Converts this map into another by copying all elements.

     [use case]

     Converts this map into another by copying all elements.

     Col

       The collection type to build.

     returns

       a new collection containing all elements of this map.

     Definition Classes
       TraversableLike → TraversableOnce → GenTraversableOnce
      Full Signature

     #### def to[Col[_]](implicit cbf: CanBuildFrom[Nothing, (A, B), Col[(A, B)]]): Col[(A, B)]

129.  def toArray: Array[A]

     [use case] Converts this map to an array.

     [use case]

     Converts this map to an array.

     returns

       an array containing all elements of this map. An `ClassTag` must be available for the element type of this map.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
      Full Signature

     #### def toArray[B >: (A, B)](implicit arg0: ClassTag[B]): Array[B]

130.  def toBuffer[B >: (A, B)]: Buffer[B]

     Uses the contents of this traversable collection to create a new mutable buffer.

     Uses the contents of this traversable collection to create a new mutable buffer.

     Note: will not terminate for infinite-sized collections.

     returns

       a buffer containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
131.  def toCollection(repr: This): Iterable[(A, B)]

     A conversion from collections of type `Repr` to `Iterable` objects.

     A conversion from collections of type `Repr` to `Iterable` objects. By default this is implemented as just a cast, but this can be overridden.

     Attributes
       protected[this]
     Definition Classes
       IterableLike → TraversableLike
132.  def toIndexedSeq: immutable.IndexedSeq[(A, B)]

     Converts this traversable collection to an indexed sequence.

     Converts this traversable collection to an indexed sequence.

     Note: will not terminate for infinite-sized collections.

     returns

       an indexed sequence containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
133.  def toIterable: Iterable[(A, B)]

     Converts this traversable collection to an iterable collection.

     Converts this traversable collection to an iterable collection. Note that the choice of target `Iterable` is lazy in this default implementation as this `TraversableOnce` may be lazy and unevaluated (i.e. it may be an iterator which is only traversable once).

     Note: will not terminate for infinite-sized collections.

     returns

       an `Iterable` containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
134.  def toIterator: Iterator[(A, B)]

     Returns an Iterator over the elements in this traversable collection.

     Returns an Iterator over the elements in this traversable collection. Will return the same Iterator if this instance is already an Iterator.

     Note: will not terminate for infinite-sized collections.

     returns

       an Iterator containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableOnce
135.  def toList: List[(A, B)]

     Converts this traversable collection to a list.

     Converts this traversable collection to a list.

     Note: will not terminate for infinite-sized collections.

     returns

       a list containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
136.  def toMap[T, U]: Map[T, U]

     [use case] Converts this map to a map.

     [use case]

     Converts this map to a map. This method is unavailable unless the elements are members of Tuple2, each ((T, U)) becoming a key-value pair in the map. Duplicate keys will be overwritten by later keys: if this is an unordered collection, which key is in the resulting map is undefined.

     returns

       a map of type `immutable.Map[T, U]` containing all key/value pairs of type `(T, U)` of this map.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
      Full Signature

     #### def toMap[T, U](implicit ev: <:<[(A, B), (T, U)]): immutable.Map[T, U]

137.  def toParArray: ParArray[T]
     Implicit
       This member is added by an implicit conversion from MapProxyLike[A, B, This] to CollectionsHaveToParArray[MapProxyLike[A, B, This], T] performed by method CollectionsHaveToParArray in scala.collection.parallel. This conversion will take place only if an implicit value of type (MapProxyLike[A, B, This]) ⇒ GenTraversableOnce[T] is in scope.
     Definition Classes
       CollectionsHaveToParArray
138.  def toSeq: Seq[(A, B)]

     Converts this traversable collection to a sequence.

     Converts this traversable collection to a sequence. As with `toIterable`, it's lazy in this default implementation, as this `TraversableOnce` may be lazy and unevaluated.

     Note: will not terminate for infinite-sized collections.

     returns

       a sequence containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
139.  def toSet[B >: (A, B)]: immutable.Set[B]

     Converts this traversable collection to a set.

     Converts this traversable collection to a set.

     Note: will not terminate for infinite-sized collections.

     returns

       a set containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableOnce → GenTraversableOnce
140.  def toStream: Stream[(A, B)]

     Converts this traversable collection to a stream.

     Converts this traversable collection to a stream.

     returns

       a stream containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableLike → GenTraversableOnce
141.  def toString(): String

     Returns a string representation of the object.

     Returns a string representation of the object.

     The default representation is platform dependent.

     returns

       a string representation of the object.

     Definition Classes
       Proxy → Any
142.  def toTraversable: Traversable[(A, B)]

     Converts this traversable collection to an unspecified Traversable.

     Converts this traversable collection to an unspecified Traversable. Will return the same collection if this instance is already Traversable.

     Note: will not terminate for infinite-sized collections.

     returns

       a Traversable containing all elements of this traversable collection.

     Definition Classes
       TraversableProxyLike → TraversableLike → TraversableOnce → GenTraversableOnce
143.  def toVector: Vector[(A, B)]

     Converts this traversable or iterator to a Vector.

     Converts this traversable or iterator to a Vector.

     Note: will not terminate for infinite-sized collections.

     returns

       a vector containing all elements of this traversable or iterator.

     Definition Classes
       TraversableOnce → GenTraversableOnce
144.  def updated(key: K, value: V): Map[K, V]

     [use case] Creates a new map obtained by updating this map with a given key/value pair.

     [use case]

     Creates a new map obtained by updating this map with a given key/value pair.

     key

       the key

     value

       the value

     returns

       A new map with the new key/value mapping added to this map.

     Definition Classes
       MapProxyLike → MapLike
      Full Signature

     #### def updated[B1 >: B](key: A, value: B1): Map[A, B1]

145.  def values: Iterable[B]

     Collects all values of this map in an iterable collection.

     Collects all values of this map in an iterable collection.

     returns

       the values of this map as an iterable.

     Definition Classes
       MapProxyLike → MapLike → GenMapLike
146.  def valuesIterator: Iterator[B]

     Creates an iterator for all values in this map.

     Creates an iterator for all values in this map.

     returns

       an iterator over all values that are associated with some key in this map.

     Definition Classes
       MapProxyLike → MapLike → GenMapLike
147.  def view(from: Int, until: Int): IterableView[(A, B), This]

     Creates a non-strict view of a slice of this iterable collection.

     Creates a non-strict view of a slice of this iterable collection.

     Note: the difference between `view` and `slice` is that `view` produces a view of the current iterable collection, whereas `slice` produces a new iterable collection.

     Note: `view(from, to)` is equivalent to `view.slice(from, to)`

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     from

       the index of the first element of the view

     until

       the index of the element following the view

     returns

       a non-strict view of a slice of this iterable collection, starting at index `from` and extending up to (but not including) index `until`.

     Definition Classes
       IterableProxyLike → TraversableProxyLike → IterableLike → TraversableLike
148.  def view: IterableView[(A, B), This]

     Creates a non-strict view of this iterable collection.

     Creates a non-strict view of this iterable collection.

     returns

       a non-strict view of this iterable collection.

     Definition Classes
       IterableProxyLike → TraversableProxyLike → IterableLike → TraversableLike
149.  final def wait(): Unit
     Definition Classes
       AnyRef
     Annotations
       @throws( ... )
150.  final def wait(arg0: Long, arg1: Int): Unit
     Definition Classes
       AnyRef
     Annotations
       @throws( ... )
151.  final def wait(arg0: Long): Unit
     Definition Classes
       AnyRef
     Annotations
       @throws( ... )
152.  def withFilter(p: ((A, B)) ⇒ Boolean): FilterMonadic[(A, B), This]

     Creates a non-strict filter of this traversable collection.

     Creates a non-strict filter of this traversable collection.

     Note: the difference between `c filter p` and `c withFilter p` is that the former creates a new collection, whereas the latter only restricts the domain of subsequent `map`, `flatMap`, `foreach`, and `withFilter` operations.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     p

       the predicate used to test elements.

     returns

       an object of class `WithFilter`, which supports `map`, `flatMap`, `foreach`, and `withFilter` operations. All these operations apply to those elements of this traversable collection which satisfy the predicate `p`.

     Definition Classes
       TraversableLike → FilterMonadic
153.  def zip[B](that: GenIterable[B]): Map[(A, B)]

     [use case] Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs.

     [use case]

     Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is longer than the other, its remaining elements are ignored.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     B

       the type of the second half of the returned pairs

     that

       The iterable providing the second half of each result pair

     returns

       a new map containing pairs consisting of corresponding elements of this map and `that`. The length of the returned collection is the minimum of the lengths of this map and `that`.

     Definition Classes
       IterableProxyLike → IterableLike → GenIterableLike
      Full Signature

     #### def zip[A1 >: (A, B), B, That](that: GenIterable[B])(implicit bf: CanBuildFrom[This, (A1, B), That]): That

154.  def zipAll[B](that: Iterable[B], thisElem: A, thatElem: B): Map[(A, B)]

     [use case] Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs.

     [use case]

     Returns a map formed from this map and another iterable collection by combining corresponding elements in pairs. If one of the two collections is shorter than the other, placeholder elements are used to extend the shorter collection to the length of the longer.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     B

       the type of the second half of the returned pairs

     that

       The iterable providing the second half of each result pair

     thisElem

       the element to be used to fill up the result if this map is shorter than `that`.

     thatElem

       the element to be used to fill up the result if `that` is shorter than this map.

     returns

       a new map containing pairs consisting of corresponding elements of this map and `that`. The length of the returned collection is the maximum of the lengths of this map and `that`. If this map is shorter than `that`, `thisElem` values are used to pad the result. If `that` is shorter than this map, `thatElem` values are used to pad the result.

     Definition Classes
       IterableProxyLike → IterableLike → GenIterableLike
      Full Signature

     #### def zipAll[B, A1 >: (A, B), That](that: GenIterable[B], thisElem: A1, thatElem: B)(implicit bf: CanBuildFrom[This, (A1, B), That]): That

155.  def zipWithIndex: Map[(A, Int)]

     [use case] Zips this map with its indices.

     [use case]

     Zips this map with its indices.

     Note: might return different results for different runs, unless the underlying collection type is ordered.

     returns

       A new map containing pairs consisting of all elements of this map paired with their index. Indices start at `0`.

     Definition Classes
       IterableProxyLike → IterableLike → GenIterableLike
      Full Signature

     #### def zipWithIndex[A1 >: (A, B), That](implicit bf: CanBuildFrom[This, (A1, Int), That]): That

     Example:

     1. `List("a", "b", "c").zipWithIndex = List(("a", 0), ("b", 1), ("c", 2))`

156.  def →[B](y: B): (MapProxyLike[A, B, This], B)
     Implicit
       This member is added by an implicit conversion from MapProxyLike[A, B, This] to ArrowAssoc[MapProxyLike[A, B, This]] performed by method ArrowAssoc in scala.Predef.
     Definition Classes
       ArrowAssoc

### Shadowed Implicit Value Members

1.  def +(other: String): String
   Implicit
     This member is added by an implicit conversion from MapProxyLike[A, B, This] to any2stringadd[MapProxyLike[A, B, This]] performed by method any2stringadd in scala.Predef.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (mapProxyLike: any2stringadd[MapProxyLike[A, B, This]]).+(other)

   Definition Classes
     any2stringadd
2.  def filter(p: ((A, B)) ⇒ Boolean): TraversableOnce[(A, B)]
   Implicit
     This member is added by an implicit conversion from MapProxyLike[A, B, This] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (mapProxyLike: MonadOps[(A, B)]).filter(p)

   Definition Classes
     MonadOps
3.  def flatMap[B](f: ((A, B)) ⇒ GenTraversableOnce[B]): TraversableOnce[B]
   Implicit
     This member is added by an implicit conversion from MapProxyLike[A, B, This] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (mapProxyLike: MonadOps[(A, B)]).flatMap(f)

   Definition Classes
     MonadOps
4.  def map[B](f: ((A, B)) ⇒ B): TraversableOnce[B]
   Implicit
     This member is added by an implicit conversion from MapProxyLike[A, B, This] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (mapProxyLike: MonadOps[(A, B)]).map(f)

   Definition Classes
     MonadOps
5.  def withFilter(p: ((A, B)) ⇒ Boolean): Iterator[(A, B)]
   Implicit
     This member is added by an implicit conversion from MapProxyLike[A, B, This] to MonadOps[(A, B)] performed by method MonadOps in scala.collection.TraversableOnce.
   Shadowing
     This implicitly inherited member is shadowed by one or more members in this class.
     To access this member you can use a type ascription:

         (mapProxyLike: MonadOps[(A, B)]).withFilter(p)

   Definition Classes
     MonadOps

### Inherited from IterableProxyLike[(A, B), This]

### Inherited from TraversableProxyLike[(A, B), This]

### Inherited from Proxy

### Inherited from MapLike[A, B, This]

### Inherited from Subtractable[A, This]

### Inherited from GenMapLike[A, B, This]

### Inherited from IterableLike[(A, B), This]

### Inherited from GenIterableLike[(A, B), This]

### Inherited from TraversableLike[(A, B), This]

### Inherited from GenTraversableLike[(A, B), This]

### Inherited from Parallelizable[(A, B), ParMap[A, B]]

### Inherited from TraversableOnce[(A, B)]

### Inherited from GenTraversableOnce[(A, B)]

### Inherited from FilterMonadic[(A, B), This]

### Inherited from HasNewBuilder[(A, B), This]

### Inherited from Equals

### Inherited from PartialFunction[A, B]

### Inherited from (A) ⇒ B

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion CollectionsHaveToParArray from MapProxyLike[A, B, This] to CollectionsHaveToParArray[MapProxyLike[A, B, This], T]

### Inherited by implicit conversion MonadOps from MapProxyLike[A, B, This] to MonadOps[(A, B)]

### Inherited by implicit conversion any2stringadd from MapProxyLike[A, B, This] to any2stringadd[MapProxyLike[A, B, This]]

### Inherited by implicit conversion StringFormat from MapProxyLike[A, B, This] to StringFormat[MapProxyLike[A, B, This]]

### Inherited by implicit conversion Ensuring from MapProxyLike[A, B, This] to Ensuring[MapProxyLike[A, B, This]]

### Inherited by implicit conversion ArrowAssoc from MapProxyLike[A, B, This] to ArrowAssoc[MapProxyLike[A, B, This]]

### Inherited by implicit conversion alternateImplicit from MapProxyLike[A, B, This] to ForceImplicitAmbiguity

### Ungrouped