# MultiMap

#### trait MultiMap[A, B] extends Map[A, Set[B]]

A trait for mutable maps with multiple values assigned to a key.

This class is typically used as a mixin. It turns maps which map A to Set[B] objects into multimaps that map A to B objects.

Example:
1. // first import all necessary types from package `collection.mutable`
import collection.mutable.{ HashMap, MultiMap, Set }

// to create a `MultiMap` the easiest way is to mixin it into a normal
// `Map` instance
val mm = new HashMap[Int, Set[String]] with MultiMap[Int, String]

// to add key-value pairs to a multimap it is important to use
// the method `addBinding` because standard methods like `+` will
// value to the existing key

// mm now contains `Map(2 -> Set(b), 1 -> Set(c, a))`

// to check if the multimap contains a value there is method
// `entryExists`, which allows to traverse the including set
mm.entryExists(1, _ == "a") == true
mm.entryExists(1, _ == "b") == false
mm.entryExists(2, _ == "b") == true

// to remove a previous added value there is the method `removeBinding`
mm.removeBinding(1, "a")
mm.entryExists(1, _ == "a") == false
Linear Supertypes
Map[A, Set[B]], MapLike[A, Set[B], Map[A, Set[B]]], Cloneable[Map[A, Set[B]]], scala.Cloneable, java.lang.Cloneable, Shrinkable[A], Builder[(A, Set[B]), Map[A, Set[B]]], Growable[(A, Set[B])], Clearable, collection.Map[A, Set[B]], collection.MapLike[A, Set[B], Map[A, Set[B]]], Subtractable[A, Map[A, Set[B]]], PartialFunction[A, Set[B]], (A) ⇒ Set[B], GenMap[A, Set[B]], GenMapLike[A, Set[B], Map[A, Set[B]]], Iterable[(A, Set[B])], collection.Iterable[(A, Set[B])], IterableLike[(A, Set[B]), Map[A, Set[B]]], Equals, GenIterable[(A, Set[B])], GenIterableLike[(A, Set[B]), Map[A, Set[B]]], Traversable[(A, Set[B])], Mutable, collection.Traversable[(A, Set[B])], GenTraversable[(A, Set[B])], GenericTraversableTemplate[(A, Set[B]), Iterable], TraversableLike[(A, Set[B]), Map[A, Set[B]]], GenTraversableLike[(A, Set[B]), Map[A, Set[B]]], Parallelizable[(A, Set[B]), ParMap[A, Set[B]]], TraversableOnce[(A, Set[B])], GenTraversableOnce[(A, Set[B])], FilterMonadic[(A, Set[B]), Map[A, Set[B]]], HasNewBuilder[(A, Set[B]), Map[A, Set[B]]], AnyRef, Any
Ordering
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Inherited
1. MultiMap
2. Map
3. MapLike
4. Cloneable
5. Cloneable
6. Cloneable
7. Shrinkable
8. Builder
9. Growable
10. Clearable
11. Map
12. MapLike
13. Subtractable
14. PartialFunction
15. Function1
16. GenMap
17. GenMapLike
18. Iterable
19. Iterable
20. IterableLike
21. Equals
22. GenIterable
23. GenIterableLike
24. Traversable
25. Mutable
26. Traversable
27. GenTraversable
28. GenericTraversableTemplate
29. TraversableLike
30. GenTraversableLike
31. Parallelizable
32. TraversableOnce
33. GenTraversableOnce
35. HasNewBuilder
36. AnyRef
37. Any
Implicitly
1. by CollectionsHaveToParArray
4. by StringFormat
5. by Ensuring
6. by ArrowAssoc
7. by alternateImplicit
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Visibility
1. Public
2. All

### Type Members

1. #### class DefaultKeySet extends AbstractSet[A] with Set[A] with Serializable

The implementation class of the set returned by keySet.

2. #### class DefaultValuesIterable extends AbstractIterable[B] with Iterable[B] with Serializable

The implementation class of the iterable returned by values.

3. #### class FilteredKeys extends AbstractMap[A, B] with DefaultMap[A, B]

Attributes
protected
Definition Classes
MapLike
4. #### class MappedValues[C] extends AbstractMap[A, C] with DefaultMap[A, C]

Attributes
protected
Definition Classes
MapLike
5. #### type Self = Map[A, Set[B]]

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.

### Abstract Value Members

1. #### abstract def +=(kv: (A, Set[B])): MultiMap.this.type

Adds a new key/value pair to this map.

Adds a new key/value pair to this map. If the map already contains a mapping for the key, it will be overridden by the new value.

kv

the key/value pair.

returns

the map itself

Definition Classes
MapLikeBuilderGrowable
2. #### abstract def -=(key: A): MultiMap.this.type

Removes a key from this map.

Removes a key from this map.

key

the key to be removed

returns

the map itself.

Definition Classes
MapLikeShrinkable
3. #### abstract def get(key: A): Option[Set[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
MapLikeGenMapLike
4. #### abstract def iterator: Iterator[(A, Set[B])]

Creates a new iterator over all key/value pairs of this map

Creates a new iterator over all key/value pairs of this map

returns

the new iterator

Definition Classes
MapLikeIterableLikeGenIterableLike

### Concrete Value Members

1. #### final def !=(arg0: Any): Boolean

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

Definition Classes
AnyRef → Any
3. #### def +[B1 >: Set[B]](elem1: (A, B1), elem2: (A, B1), elems: (A, B1)*): Map[A, B1]

Creates a new map containing two or more key/value mappings and all the key/value mappings of this map.

Creates a new map containing two or more key/value mappings and all the key/value mappings of this map.

Specified mappings will override existing mappings from this map with the same keys.

B1

the type of the added values

elem1

elem2

elems

returns

a new map containing mappings of this map and two or more specified mappings.

Definition Classes
MapLikeMapLike
Annotations
@migration
Migration

(Changed in version 2.8.0) + creates a new map. Use += to add an element to this map and return that map itself.

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

Creates a new map containing a new key/value mapping and all the key/value mappings of this map.

Creates a new map containing a new key/value mapping and all the key/value mappings of this map.

Mapping kv will override existing mappings from this map with the same key.

B1

the type of the value in the key/value pair.

kv

the key/value mapping to be added

returns

a new map containing mappings of this map and the mapping kv.

Definition Classes
MapLikeMapLikeGenMapLike
Annotations
@migration
Migration

(Changed in version 2.8.0) + creates a new map. Use += to add an element to this map and return that map itself.

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

Creates a new map containing the key/value mappings provided by the specified traversable object and all the key/value mappings of this map.

Creates a new map containing the key/value mappings provided by the specified traversable object and all the key/value mappings of this map.

Note that existing mappings from this map with the same key as those in xs will be overriden.

B1

the type of the added values

xs

the traversable object.

returns

a new map containing mappings of this map and those provided by xs.

Definition Classes
MapLikeMapLike
Annotations
@migration
Migration

(Changed in version 2.8.0) ++ creates a new map. Use ++= to add an element to this map and return that map itself.

6. #### def ++[B](that: GenTraversableOnce[B]): MultiMap[B]

[use case] Returns a new multimap containing the elements from the left hand operand followed by the elements from the right hand operand.

[use case]

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

Example:

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

scala> val b = List(2)
b: List[Int] = List(2)

scala> val c = a ++ b
c: List[Int] = List(1, 2)

scala> val d = List('a')
d: List[Char] = List(a)

scala> val e = c ++ d
e: List[AnyVal] = List(1, 2, a)
B

the element type of the returned collection.

that

the traversable to append.

returns

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

Definition Classes
TraversableLikeGenTraversableLike
Full Signature

7. #### def ++:[B >: (A, Set[B]), That](that: collection.Traversable[B])(implicit bf: CanBuildFrom[Map[A, Set[B]], 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 z = x ++: y

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 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]): MultiMap[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 z = x ++: y
B

the element type of the returned collection.

that

the traversable to append.

returns

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

Definition Classes
TraversableLike
Full Signature

9. #### def ++=(xs: TraversableOnce[(A, Set[B])]): MultiMap.this.type

adds all elements produced by a TraversableOnce to this growable collection.

adds all elements produced by a TraversableOnce to this growable collection.

xs

the TraversableOnce producing the elements to add.

returns

the growable collection itself.

Definition Classes
Growable
10. #### def +=(elem1: (A, Set[B]), elem2: (A, Set[B]), elems: (A, Set[B])*): MultiMap.this.type

adds two or more elements to this growable collection.

adds two or more elements to this growable collection.

elem1

elem2

elems

returns

the growable collection itself

Definition Classes
Growable
11. #### def -(elem1: A, elem2: A, elems: A*): Map[A, Set[B]]

Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of the two or more specified keys.

Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of the two or more specified keys.

elem1

the first element to remove.

elem2

the second element to remove.

elems

the remaining elements to remove.

returns

a new map containing all the mappings of this map except mappings with a key equal to elem1, elem2 or any of elems.

Definition Classes
MapLikeSubtractable
Annotations
@migration
Migration

(Changed in version 2.8.0) - creates a new map. Use -= to remove an element from this map and return that map itself.

12. #### def -(key: A): Map[A, Set[B]]

Creates a new map with all the key/value mappings of this map except the key/value mapping with the specified key.

Creates a new map with all the key/value mappings of this map except the key/value mapping with the specified key.

key

the key to be removed

returns

a new map with all the mappings of this map except that with a key key.

Definition Classes
MapLikeMapLikeSubtractableGenMapLike
Annotations
@migration
Migration

(Changed in version 2.8.0) - creates a new map. Use -= to remove an element from this map and return that map itself.

13. #### def --(xs: GenTraversableOnce[A]): Map[A, Set[B]]

Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of those provided by the specified traversable object.

Creates a new map with all the key/value mappings of this map except mappings with keys equal to any of those provided by the specified traversable object.

xs

the traversable object.

returns

a new map with all the key/value mappings of this map except mappings with a key equal to a key from xs.

Definition Classes
MapLikeSubtractable
Annotations
@migration
Migration

(Changed in version 2.8.0) -- creates a new map. Use --= to remove an element from this map and return that map itself.

14. #### def --=(xs: TraversableOnce[A]): MultiMap.this.type

Removes all elements produced by an iterator from this shrinkable collection.

Removes all elements produced by an iterator from this shrinkable collection.

xs

the iterator producing the elements to remove.

returns

the shrinkable collection itself

Definition Classes
Shrinkable
15. #### def -=(elem1: A, elem2: A, elems: A*): MultiMap.this.type

Removes two or more elements from this shrinkable collection.

Removes two or more elements from this shrinkable collection.

elem1

the first element to remove.

elem2

the second element to remove.

elems

the remaining elements to remove.

returns

the shrinkable collection itself

Definition Classes
Shrinkable
16. #### def ->[B](y: B): (MultiMap[A, B], B)

Implicit information
This member is added by an implicit conversion from MultiMap[A, B] to ArrowAssoc[MultiMap[A, B]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
()
17. #### def /:[B](z: B)(op: (B, (A, Set[B])) ⇒ B): B

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

Applies a binary operator to a start value and all elements of this traversable or iterator, 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 or iterator, 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 or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
18. #### def :\[B](z: B)(op: ((A, Set[B]), B) ⇒ B): B

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

Applies a binary operator to all elements of this traversable or iterator 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 or iterator, 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 or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
19. #### final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
20. #### def addBinding(key: A, value: B): MultiMap.this.type

Assigns the specified value to a specified key, replacing the existing value assigned to that key if it is equal to the specified value.

Assigns the specified value to a specified key, replacing the existing value assigned to that key if it is equal to the specified value. Otherwise, simply adds another binding to the key.

key

The key to which to bind the new value.

value

The value to bind to the key.

returns

A reference to this multimap.

21. #### def addString(b: scala.StringBuilder, start: String, sep: String, end: String): scala.StringBuilder

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

Appends all bindings 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 of all bindings of this map in the form of key -> value are separated by the string sep.

b

the builder to which strings 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
MapLikeTraversableOnce
22. #### def addString(b: scala.StringBuilder): scala.StringBuilder

Appends all elements of this traversable or iterator to a string builder.

Appends all elements of this traversable or iterator to a string builder. The written text consists of the string representations (w.r.t. the method toString) of all elements of this traversable or iterator 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 =

h: StringBuilder = 1234
b

the string builder to which elements are appended.

returns

the string builder b to which elements were appended.

Definition Classes
TraversableOnce
23. #### def addString(b: scala.StringBuilder, sep: String): scala.StringBuilder

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

Appends all elements of this traversable or iterator 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 or iterator, 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 =

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
TraversableOnce
24. #### def aggregate[B](z: ⇒ B)(seqop: (B, (A, Set[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 has similar semantics, but does not require the result to be a supertype of the element type. It traverses the elements in different partitions sequentially, using seqop to update the result, and then applies combop to results from different partitions. The implementation of this operation may operate on an arbitrary number of collection partitions, so combop may be invoked an arbitrary number of times.

For example, one might want to process some elements and then produce a Set. In this case, seqop would process an element and append it to the list, while combop would concatenate two lists from different partitions together. The initial value z would be an empty set.

pc.aggregate(Set[Int]())(_ += process(_), _ ++ _)

Another example is calculating geometric mean from a collection of doubles (one would typically require big doubles for this).

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
TraversableOnceGenTraversableOnce
25. #### def andThen[C](k: (Set[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
PartialFunctionFunction1
26. #### def apply(key: A): Set[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
MapLikeGenMapLikeFunction1
27. #### def applyOrElse[A1 <: A, B1 >: Set[B]](x: A1, default: (A1) ⇒ B1): B1

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 compiler generates 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
PartialFunction
Since

2.10

28. #### final def asInstanceOf[T0]: T0

Definition Classes
Any
29. #### 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
IterableLikeEquals
30. #### def clear(): Unit

Removes all bindings from the map.

Removes all bindings from the map. After this operation has completed, the map will be empty.

Definition Classes
MapLikeBuilderGrowableClearable
31. #### def clone(): Map[A, Set[B]]

Definition Classes
MapLikeCloneable → AnyRef
32. #### def collect[B](pf: PartialFunction[A, B]): MultiMap[B]

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

[use case]

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

B

the element type of the returned collection.

pf

the partial function which filters and maps the multimap.

returns

a new multimap 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
TraversableLikeGenTraversableLike
Full Signature

33. #### def collectFirst[B](pf: PartialFunction[(A, Set[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)

34. #### def companion: GenericCompanion[Iterable]

The factory companion object that builds instances of class Iterable.

The factory companion object that builds instances of class Iterable. (or its Iterable superclass where class Iterable is not a Seq.)

Definition Classes
IterableIterableGenIterableTraversableTraversableGenTraversableGenericTraversableTemplate
35. #### def compose[A](g: (A) ⇒ A): (A) ⇒ Set[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
()
36. #### 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
MapLikeGenMapLike
37. #### def copyToArray(xs: Array[A], start: Int, len: Int): Unit

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

[use case]

Copies elements of this multimap to an array. Fills the given array xs with at most len elements of this multimap, starting at position start. Copying will stop once either the end of the current multimap is reached, or the end of the 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
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
Full Signature

38. #### def copyToArray(xs: Array[A]): Unit

[use case] Copies values of this multimap to an array.

[use case]

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

xs

the array to fill.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

39. #### def copyToArray(xs: Array[A], start: Int): Unit

[use case] Copies values of this multimap to an array.

[use case]

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

xs

the array to fill.

start

the starting index.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

40. #### def copyToBuffer[B >: (A, Set[B])](dest: Buffer[B]): Unit

Copies all elements of this traversable or iterator to a buffer.

Copies all elements of this traversable or iterator to a buffer.

Note: will not terminate for infinite-sized collections.

dest

The buffer to which elements are copied.

Definition Classes
TraversableOnce
41. #### def count(p: ((A, Set[B])) ⇒ Boolean): Int

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

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

p

the predicate used to test elements.

returns

the number of elements satisfying the predicate p.

Definition Classes
TraversableOnceGenTraversableOnce
42. #### def default(key: A): Set[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
MapLikeGenMapLike
Exceptions thrown
`NoSuchElementException`

43. #### def drop(n: Int): Map[A, Set[B]]

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 iterable collection.

returns

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

Definition Classes
IterableLikeTraversableLikeGenTraversableLike
44. #### def dropRight(n: Int): Map[A, Set[B]]

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
IterableLike
45. #### def dropWhile(p: ((A, Set[B])) ⇒ Boolean): Map[A, Set[B]]

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
TraversableLikeGenTraversableLike
46. #### def empty: Map[A, Set[B]]

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
MapMapMapLike
47. #### def ensuring(cond: (MultiMap[A, B]) ⇒ Boolean, msg: ⇒ Any): MultiMap[A, B]

Implicit information
This member is added by an implicit conversion from MultiMap[A, B] to Ensuring[MultiMap[A, B]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
48. #### def ensuring(cond: (MultiMap[A, B]) ⇒ Boolean): MultiMap[A, B]

Implicit information
This member is added by an implicit conversion from MultiMap[A, B] to Ensuring[MultiMap[A, B]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
49. #### def ensuring(cond: Boolean, msg: ⇒ Any): MultiMap[A, B]

Implicit information
This member is added by an implicit conversion from MultiMap[A, B] to Ensuring[MultiMap[A, B]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
50. #### def ensuring(cond: Boolean): MultiMap[A, B]

Implicit information
This member is added by an implicit conversion from MultiMap[A, B] to Ensuring[MultiMap[A, B]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
51. #### def entryExists(key: A, p: (B) ⇒ Boolean): Boolean

Checks if there exists a binding to key such that it satisfies the predicate p.

Checks if there exists a binding to key such that it satisfies the predicate p.

key

The key for which the predicate is checked.

p

The predicate which a value assigned to the key must satisfy.

returns

A boolean if such a binding exists

52. #### final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
53. #### def equals(that: Any): Boolean

Compares two maps structurally; i.

Compares two maps structurally; i.e. checks if all mappings contained in this map are also contained in the other map, and vice versa.

that

the other map

returns

true if both maps contain exactly the same mappings, false otherwise.

Definition Classes
GenMapLikeEquals → AnyRef → Any
54. #### def exists(p: ((A, Set[B])) ⇒ Boolean): Boolean

Tests whether a predicate holds for some of the elements of this iterable collection.

Tests whether a predicate holds for some of the elements of this iterable collection.

Note: may not terminate for infinite-sized collections.

p

the predicate used to test elements.

returns

true if the given predicate p holds for some of the elements of this iterable collection, otherwise false.

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
55. #### def filter(p: ((A, Set[B])) ⇒ Boolean): Map[A, Set[B]]

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
TraversableLikeGenTraversableLike
56. #### def filterKeys(p: (A) ⇒ Boolean): collection.Map[A, Set[B]]

Filters this map by retaining only keys satisfying a predicate.

Filters this map by retaining only keys satisfying a predicate.

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
MapLikeGenMapLike
57. #### def filterNot(p: ((A, Set[B])) ⇒ Boolean): Map[A, Set[B]]

Returns a new map obtained by removing all key/value pairs for which the predicate p returns true.

Returns a new map obtained by removing all key/value pairs for which the predicate p returns true.

Note: This method works by successively removing elements for which the predicate is true from this set. If removal is slow, or you expect that most elements of the set will be removed, you might consider using filter with a negated predicate instead.

p

A predicate over key-value pairs

returns

A new map containing elements not satisfying the predicate.

Definition Classes
MapLikeTraversableLikeGenTraversableLike
58. #### def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
( classOf[java.lang.Throwable] )
59. #### def find(p: ((A, Set[B])) ⇒ Boolean): Option[(A, Set[B])]

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

Finds the first element of the iterable 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 iterable collection that satisfies p, or None if none exists.

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
60. #### def flatMap[B](f: (A) ⇒ GenTraversableOnce[B]): MultiMap[B]

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

[use case]

Builds a new collection by applying a function to all elements of this multimap 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 multimap. 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 multimap resulting from applying the given collection-valued function f to each element of this multimap and concatenating the results.

Definition Classes
Full Signature

61. #### def flatten[B]: MultiMap[B]

[use case] Converts this multimap of traversable collections into a multimap formed by the elements of these traversable collections.

[use case]

Converts this multimap of traversable collections into a multimap formed by the elements of these traversable collections.

The resulting collection's type will be guided by the static type of multimap. For example:

val xs = List(
Set(1, 2, 3),
Set(1, 2, 3)
).flatten
// xs == List(1, 2, 3, 1, 2, 3)

val ys = Set(
List(1, 2, 3),
List(3, 2, 1)
).flatten
// ys == Set(1, 2, 3)
B

the type of the elements of each traversable collection.

returns

a new multimap resulting from concatenating all element multimaps.

Definition Classes
GenericTraversableTemplate
Full Signature

62. #### def fold[A1 >: (A, Set[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.

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 fold operator op between all the elements and z

Definition Classes
TraversableOnceGenTraversableOnce
63. #### def foldLeft[B](z: B)(op: (B, (A, Set[B])) ⇒ B): B

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

Applies a binary operator to a start value and all elements of this traversable or iterator, 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 or iterator, 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 or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
64. #### def foldRight[B](z: B)(op: ((A, Set[B]), B) ⇒ B): B

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

Applies a binary operator to all elements of this iterable 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 iterable 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 iterable collection.

Definition Classes
IterableLikeTraversableOnceGenTraversableOnce
65. #### def forall(p: ((A, Set[B])) ⇒ Boolean): Boolean

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

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

Note: may not terminate for infinite-sized collections.

p

the predicate used to test elements.

returns

true if the given predicate p holds for all elements of this iterable collection, otherwise false.

Definition Classes
IterableLikeTraversableLikeTraversableOnceGenTraversableOnce
66. #### def foreach(f: ((A, Set[B])) ⇒ Unit): Unit

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

[use case]

Applies a function f to all elements of this multimap.

Note: this method underlies the implementation of most other bulk operations. Subclasses should re-implement this method if a more efficient implementation exists.

f

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

Definition Classes
Full Signature

67. #### 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 information
This member is added by an implicit conversion from MultiMap[A, B] to StringFormat[MultiMap[A, B]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
()
68. #### def genericBuilder[B]: Builder[B, Iterable[B]]

The generic builder that builds instances of CC at arbitrary element types.

The generic builder that builds instances of CC at arbitrary element types.

Definition Classes
GenericTraversableTemplate
69. #### final def getClass(): Class[_]

Definition Classes
AnyRef → Any
70. #### def getOrElse(key: A, default: ⇒ Set[B]): Set[B]

[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
MapLikeGenMapLike
Full Signature

71. #### def getOrElseUpdate(key: A, op: ⇒ Set[B]): Set[B]

If given key is already in this map, returns associated value.

If given key is already in this map, returns associated value.

Otherwise, computes value from given expression op, stores with key in map and returns that value.

key

the key to test

op

the computation yielding the value to associate with key, if key is previously unbound.

returns

the value associated with key (either previously or as a result of executing the method).

Definition Classes
MapLike
72. #### def groupBy[K](f: ((A, Set[B])) ⇒ K): immutable.Map[K, Map[A, Set[B]]]

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
TraversableLikeGenTraversableLike
73. #### def grouped(size: Int): Iterator[Map[A, Set[B]]]

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
IterableLike

scala.collection.Iterator, method grouped

74. #### 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.

Note: many collection methods will not work on collections of infinite sizes.

returns

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

Definition Classes
TraversableLikeTraversableOnceGenTraversableOnce
75. #### def hashCode(): Int

Definition Classes
GenMapLike → AnyRef → Any
76. #### def head: (A, Set[B])

Selects the first element of this iterable collection.

Selects the first element of this iterable collection.

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

returns

the first element of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike
Exceptions thrown
`NoSuchElementException`

if the iterable collection is empty.

77. #### def headOption: Option[(A, Set[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
TraversableLikeGenTraversableLike
78. #### def init: Map[A, Set[B]]

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
TraversableLikeGenTraversableLike
Exceptions thrown
`UnsupportedOperationException`

if the traversable collection is empty.

79. #### def inits: Iterator[Map[A, Set[B]]]

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)

80. #### 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
MapLikeGenMapLikePartialFunction
81. #### def isEmpty: Boolean

Tests whether the map is empty.

Tests whether the map is empty.

returns

true if the map does not contain any key/value binding, false otherwise.

Definition Classes
MapLikeIterableLikeTraversableLikeTraversableOnceGenTraversableOnce
82. #### final def isInstanceOf[T0]: Boolean

Definition Classes
Any
83. #### 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
TraversableLikeGenTraversableLikeGenTraversableOnce
84. #### def keySet: collection.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
MapLikeGenMapLike
85. #### def keys: collection.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
MapLikeGenMapLike
Annotations
@migration
Migration

(Changed in version 2.8.0) keys returns Iterable[A] rather than Iterator[A].

86. #### def keysIterator: Iterator[A]

Creates an iterator for all keys.

Creates an iterator for all keys.

returns

an iterator over all keys.

Definition Classes
MapLikeGenMapLike
87. #### def last: (A, Set[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
TraversableLikeGenTraversableLike
Exceptions thrown
NoSuchElementException

If the traversable collection is empty.

88. #### def lastOption: Option[(A, Set[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
TraversableLikeGenTraversableLike
89. #### def lift: (A) ⇒ Option[Set[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

Function.unlift

90. #### def makeSet: Set[B]

Creates a new set.

Creates a new set.

Classes that use this trait as a mixin can override this method to have the desired implementation of sets assigned to new keys. By default this is HashSet.

returns

An empty set of values of type B.

Attributes
protected
91. #### def map[B](f: (A) ⇒ B): MultiMap[B]

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

[use case]

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

B

the element type of the returned collection.

f

the function to apply to each element.

returns

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

Definition Classes
Full Signature

92. #### def mapResult[NewTo](f: (Map[A, Set[B]]) ⇒ NewTo): Builder[(A, Set[B]), NewTo]

Creates a new builder by applying a transformation function to the results of this builder.

Creates a new builder by applying a transformation function to the results of this builder.

NewTo

the type of collection returned by f.

f

the transformation function.

returns

a new builder which is the same as the current builder except that a transformation function is applied to this builder's result.

Definition Classes
Builder
93. #### def mapValues[C](f: (Set[B]) ⇒ C): collection.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
MapLikeGenMapLike
94. #### def max: A

[use case] Finds the largest element.

[use case]

Finds the largest element.

returns

the largest element of this multimap.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

95. #### 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 multimap with the largest value measured by function f.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

96. #### def min: A

[use case] Finds the smallest element.

[use case]

Finds the smallest element.

returns

the smallest element of this multimap

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

97. #### 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 multimap with the smallest value measured by function f.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

98. #### def mkString: String

Displays all elements of this traversable or iterator in a string.

Displays all elements of this traversable or iterator in a string.

returns

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

Definition Classes
TraversableOnceGenTraversableOnce
99. #### def mkString(sep: String): String

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

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

sep

the separator string.

returns

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

Definition Classes
TraversableOnceGenTraversableOnce
Example:
1. List(1, 2, 3).mkString("|") = "1|2|3"

100. #### def mkString(start: String, sep: String, end: String): String

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

Displays all elements of this traversable or iterator 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 or iterator. 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 or iterator are separated by the string sep.

Definition Classes
TraversableOnceGenTraversableOnce
Example:
1. List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"

101. #### final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
102. #### def newBuilder: Builder[(A, Set[B]), Map[A, Set[B]]]

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

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

Overrides MapLike implementation for better efficiency.

Attributes
protected[this]
Definition Classes
MapLikeMapLikeTraversableLikeHasNewBuilder
103. #### def nonEmpty: Boolean

Tests whether the traversable or iterator is not empty.

Tests whether the traversable or iterator is not empty.

returns

true if the traversable or iterator contains at least one element, false otherwise.

Definition Classes
TraversableOnceGenTraversableOnce
104. #### final def notify(): Unit

Definition Classes
AnyRef
105. #### final def notifyAll(): Unit

Definition Classes
AnyRef
106. #### def orElse[A1 <: A, B1 >: Set[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
107. #### def par: ParMap[A, Set[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
108. #### def parCombiner: Combiner[(A, Set[B]), ParMap[A, Set[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
MapLikeMapLikeTraversableLikeParallelizable
109. #### def partition(p: ((A, Set[B])) ⇒ Boolean): (Map[A, Set[B]], Map[A, Set[B]])

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
TraversableLikeGenTraversableLike
110. #### 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 multimap 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 multimap and as result type of product. Examples of such types are: Long, Float, Double, BigInt.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

111. #### def put(key: A, value: Set[B]): Option[Set[B]]

Adds a new key/value pair to this map and optionally returns previously bound value.

Adds a new key/value pair to this map and optionally returns previously bound value. If the map already contains a mapping for the key, it will be overridden by the new value.

key

the key to update

value

the new value

returns

an option value containing the value associated with the key before the put operation was executed, or None if key was not defined in the map before.

Definition Classes
MapLike
112. #### def reduce[A1 >: (A, Set[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
TraversableOnceGenTraversableOnce
Exceptions thrown
UnsupportedOperationException

if this traversable or iterator is empty.

113. #### def reduceLeft[B >: (A, Set[B])](op: (B, (A, Set[B])) ⇒ B): B

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

Applies a binary operator to all elements of this traversable or iterator, 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 or iterator, 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 or iterator.

Definition Classes
TraversableOnce
Exceptions thrown
`UnsupportedOperationException`

if this traversable or iterator is empty.

114. #### def reduceLeftOption[B >: (A, Set[B])](op: (B, (A, Set[B])) ⇒ B): Option[B]

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

Optionally applies a binary operator to all elements of this traversable or iterator, 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) is this traversable or iterator is nonempty, None otherwise.

Definition Classes
TraversableOnceGenTraversableOnce
115. #### def reduceOption[A1 >: (A, Set[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
TraversableOnceGenTraversableOnce
116. #### def reduceRight[B >: (A, Set[B])](op: ((A, Set[B]), B) ⇒ B): B

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

Applies a binary operator to all elements of this iterable 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 iterable 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 iterable collection.

Definition Classes
IterableLikeTraversableOnceGenTraversableOnce
Exceptions thrown
`UnsupportedOperationException`

if this iterable collection is empty.

117. #### def reduceRightOption[B >: (A, Set[B])](op: ((A, Set[B]), B) ⇒ B): Option[B]

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

Optionally applies a binary operator to all elements of this traversable or iterator, 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) is this traversable or iterator is nonempty, None otherwise.

Definition Classes
TraversableOnceGenTraversableOnce
118. #### def remove(key: A): Option[Set[B]]

Removes a key from this map, returning the value associated previously with that key as an option.

Removes a key from this map, returning the value associated previously with that key as an option.

key

the key to be removed

returns

an option value containing the value associated previously with key, or None if key was not defined in the map before.

Definition Classes
MapLike
119. #### def removeBinding(key: A, value: B): MultiMap.this.type

Removes the binding of value to key if it exists, otherwise this operation doesn't have any effect.

Removes the binding of value to key if it exists, otherwise this operation doesn't have any effect.

If this was the last value assigned to the specified key, the set assigned to that key will be removed as well.

key

The key of the binding.

value

The value to remove.

returns

A reference to this multimap.

120. #### def repr: Map[A, Set[B]]

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
TraversableLikeGenTraversableLike
121. #### def result(): Map[A, Set[B]]

The result when this map is used as a builder

The result when this map is used as a builder

returns

the map representation itself.

Definition Classes
MapLikeBuilder
122. #### def retain(p: (A, Set[B]) ⇒ Boolean): MultiMap.this.type

Retains only those mappings for which the predicate p returns true.

Retains only those mappings for which the predicate p returns true.

p

The test predicate

Definition Classes
MapLike
123. #### def reversed: List[(A, Set[B])]

Attributes
protected[this]
Definition Classes
TraversableOnce
124. #### def runWith[U](action: (Set[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

applyOrElse.

125. #### def sameElements(that: GenIterable[A]): Boolean

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

[use case]

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

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
IterableLikeGenIterableLike
Full Signature

126. #### def scan[B >: (A, Set[B]), That](z: B)(op: (B, B) ⇒ B)(implicit cbf: CanBuildFrom[Map[A, Set[B]], 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
TraversableLikeGenTraversableLike
127. #### def scanLeft[B, That](z: B)(op: (B, (A, Set[B])) ⇒ B)(implicit bf: CanBuildFrom[Map[A, Set[B]], 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 and the new element type B.

returns

collection with intermediate results

Definition Classes
TraversableLikeGenTraversableLike
128. #### def scanRight[B, That](z: B)(op: ((A, Set[B]), B) ⇒ B)(implicit bf: CanBuildFrom[Map[A, Set[B]], 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 and the new element type B.

returns

collection with intermediate results

Definition Classes
TraversableLikeGenTraversableLike
Annotations
@migration
Migration

(Changed in version 2.9.0) The behavior of scanRight has changed. The previous behavior can be reproduced with scanRight.reverse.

129. #### def seq: Map[A, Set[B]]

A version of this collection with all of the operations implemented sequentially (i.

A version of this collection with all of the operations implemented sequentially (i.e. in a single-threaded manner).

This method returns a reference to this collection. In parallel collections, it is redefined to return a sequential implementation of this collection. In both cases, it has O(1) complexity.

returns

a sequential view of the collection.

Definition Classes
MapMapGenMapGenMapLikeIterableIterableGenIterableTraversableTraversableGenTraversableParallelizableTraversableOnceGenTraversableOnce
130. #### def size: Int

The size of this traversable or iterator.

The size of this traversable or iterator.

Note: will not terminate for infinite-sized collections.

returns

the number of elements in this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
131. #### def sizeHint(coll: TraversableLike[_, _], delta: Int): Unit

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta.

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

coll

the collection which serves as a hint for the result's size.

delta

a correction to add to the coll.size to produce the size hint.

Definition Classes
Builder
132. #### def sizeHint(coll: TraversableLike[_, _]): Unit

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta.

Gives a hint that one expects the result of this builder to have the same size as the given collection, plus some delta. This will provide a hint only if the collection is known to have a cheap size method. Currently this is assumed to be the case if and only if the collection is of type IndexedSeqLike. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

coll

the collection which serves as a hint for the result's size.

Definition Classes
Builder
133. #### def sizeHint(size: Int): Unit

Gives a hint how many elements are expected to be added when the next result is called.

Gives a hint how many elements are expected to be added when the next result is called. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

size

the hint how many elements will be added.

Definition Classes
Builder
134. #### def sizeHintBounded(size: Int, boundingColl: TraversableLike[_, _]): Unit

Gives a hint how many elements are expected to be added when the next result is called, together with an upper bound given by the size of some other collection.

Gives a hint how many elements are expected to be added when the next result is called, together with an upper bound given by the size of some other collection. Some builder classes will optimize their representation based on the hint. However, builder implementations are still required to work correctly even if the hint is wrong, i.e. a different number of elements is added.

size

the hint how many elements will be added.

boundingColl

the bounding collection. If it is an IndexedSeqLike, then sizes larger than collection's size are reduced.

Definition Classes
Builder
135. #### def slice(from: Int, until: Int): Map[A, Set[B]]

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

Definition Classes
IterableLikeTraversableLikeGenTraversableLike
136. #### def sliding(size: Int, step: Int): Iterator[Map[A, Set[B]]]

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 (defaults to 1)

returns

An iterator producing iterable collections of size size, except the last and the only element will be truncated if there are fewer elements than size.

Definition Classes
IterableLike

scala.collection.Iterator, method sliding

137. #### def sliding(size: Int): Iterator[Map[A, Set[B]]]

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

returns

An iterator producing iterable collections of size size, except the last and the only element will be truncated if there are fewer elements than size.

Definition Classes
IterableLike

scala.collection.Iterator, method sliding

138. #### def span(p: ((A, Set[B])) ⇒ Boolean): (Map[A, Set[B]], Map[A, Set[B]])

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
TraversableLikeGenTraversableLike
139. #### def splitAt(n: Int): (Map[A, Set[B]], Map[A, Set[B]])

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
TraversableLikeGenTraversableLike
140. #### 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 map. Unless overridden in subclasses, the string prefix of every map is "Map".

Definition Classes
MapLikeTraversableLikeGenTraversableLike
141. #### 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 multimap 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 multimap and as result type of sum. Examples of such types are: Long, Float, Double, BigInt.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

142. #### final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
143. #### def tail: Map[A, Set[B]]

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
TraversableLikeGenTraversableLike
Exceptions thrown
`UnsupportedOperationException`

if the traversable collection is empty.

144. #### def tails: Iterator[Map[A, Set[B]]]

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)

145. #### def take(n: Int): Map[A, Set[B]]

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 iterable collection.

returns

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

Definition Classes
IterableLikeTraversableLikeGenTraversableLike
146. #### def takeRight(n: Int): Map[A, Set[B]]

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
IterableLike
147. #### def takeWhile(p: ((A, Set[B])) ⇒ Boolean): Map[A, Set[B]]

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 iterable collection whose elements all satisfy the predicate p.

Definition Classes
IterableLikeTraversableLikeGenTraversableLike
148. #### def thisCollection: collection.Iterable[(A, Set[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
IterableLikeTraversableLike
149. #### def to[Col[_]]: Col[A]

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

[use case]

Converts this multimap into another by copying all elements.

Col

The collection type to build.

returns

a new collection containing all elements of this multimap.

Definition Classes
TraversableLikeTraversableOnceGenTraversableOnce
Full Signature

150. #### def toArray: Array[A]

[use case] Converts this multimap to an array.

[use case]

Converts this multimap to an array.

returns

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

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

151. #### def toBuffer[C >: (A, Set[B])]: Buffer[C]

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

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

returns

a buffer containing all elements of this map.

Definition Classes
MapLikeTraversableOnceGenTraversableOnce
152. #### def toCollection(repr: Map[A, Set[B]]): collection.Iterable[(A, Set[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
IterableLikeTraversableLike
153. #### def toIndexedSeq: immutable.IndexedSeq[(A, Set[B])]

Converts this traversable or iterator to an indexed sequence.

Converts this traversable or iterator to an indexed sequence.

Note: will not terminate for infinite-sized collections.

returns

an indexed sequence containing all elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
154. #### def toIterable: collection.Iterable[(A, Set[B])]

Returns this iterable collection as an iterable collection.

Returns this iterable collection as an iterable collection.

A new collection will not be built; lazy collections will stay lazy.

Note: will not terminate for infinite-sized collections.

returns

an Iterable containing all elements of this iterable collection.

Definition Classes
IterableLikeTraversableOnceGenTraversableOnce
155. #### def toIterator: Iterator[(A, Set[B])]

Returns an Iterator over the elements in this iterable collection.

Returns an Iterator over the elements in this iterable collection. Produces the same result as iterator.

Note: will not terminate for infinite-sized collections.

returns

an Iterator containing all elements of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableOnce
Annotations
@deprecatedOverriding( ... , "2.11.0" )
156. #### def toList: List[(A, Set[B])]

Converts this traversable or iterator to a list.

Converts this traversable or iterator to a list.

Note: will not terminate for infinite-sized collections.

returns

a list containing all elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
157. #### def toMap[T, U]: collection.Map[T, U]

[use case] Converts this multimap to a map.

[use case]

Converts this multimap 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 multimap.

Definition Classes
TraversableOnceGenTraversableOnce
Full Signature

158. #### def toParArray: ParArray[T]

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

Converts this map to a sequence.

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

returns

a sequence containing all elements of this map.

Definition Classes
MapLikeTraversableOnceGenTraversableOnce
160. #### def toSet[B >: (A, Set[B])]: immutable.Set[B]

Converts this traversable or iterator to a set.

Converts this traversable or iterator to a set.

Note: will not terminate for infinite-sized collections.

returns

a set containing all elements of this traversable or iterator.

Definition Classes
TraversableOnceGenTraversableOnce
161. #### def toStream: immutable.Stream[(A, Set[B])]

Converts this iterable collection to a stream.

Converts this iterable collection to a stream.

Note: will not terminate for infinite-sized collections.

returns

a stream containing all elements of this iterable collection.

Definition Classes
IterableLikeTraversableLikeGenTraversableOnce
162. #### def toString(): String

Converts this map to a string.

Converts this map to a string.

returns

a string representation of this collection. By default this string consists of the stringPrefix of this map, followed by all elements separated by commas and enclosed in parentheses.

Definition Classes
MapLikeTraversableLikeFunction1 → AnyRef → Any
163. #### def toTraversable: collection.Traversable[(A, Set[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
TraversableLikeTraversableOnceGenTraversableOnce
Annotations
@deprecatedOverriding( ... , "2.11.0" )
164. #### def toVector: Vector[(A, Set[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
TraversableOnceGenTraversableOnce
165. #### def transform(f: (A, Set[B]) ⇒ Set[B]): MultiMap.this.type

Applies a transformation function to all values contained in this map.

Applies a transformation function to all values contained in this map. The transformation function produces new values from existing keys associated values.

f

the transformation to apply

returns

the map itself.

Definition Classes
MapLike
166. #### def transpose[B](implicit asTraversable: ((A, Set[B])) ⇒ GenTraversableOnce[B]): Iterable[Iterable[B]]

Transposes this collection of traversable collections into a collection of collections.

Transposes this collection of traversable collections into a collection of collections.

The resulting collection's type will be guided by the static type of collection. For example:

val xs = List(
Set(1, 2, 3),
Set(4, 5, 6)).transpose
// xs == List(
//         List(1, 4),
//         List(2, 5),
//         List(3, 6))

val ys = Vector(
List(1, 2, 3),
List(4, 5, 6)).transpose
// ys == Vector(
//         Vector(1, 4),
//         Vector(2, 5),
//         Vector(3, 6))
B

the type of the elements of each traversable collection.

asTraversable

an implicit conversion which asserts that the element type of this collection is a Traversable.

returns

a two-dimensional collection of collections which has as nth row the nth column of this collection.

Definition Classes
GenericTraversableTemplate
Annotations
@migration
Migration

(Changed in version 2.9.0) transpose throws an IllegalArgumentException if collections are not uniformly sized.

Exceptions thrown
`IllegalArgumentException`

if all collections in this collection are not of the same size.

167. #### def unzip[A1, A2](implicit asPair: ((A, Set[B])) ⇒ (A1, A2)): (Iterable[A1], Iterable[A2])

Converts this collection of pairs into two collections of the first and second half of each pair.

Converts this collection of pairs into two collections of the first and second half of each pair.

val xs = CC(
(1, "one"),
(2, "two"),
(3, "three")).unzip
// xs == (CC(1, 2, 3),
//        CC(one, two, three))
A1

the type of the first half of the element pairs

A2

the type of the second half of the element pairs

asPair

an implicit conversion which asserts that the element type of this collection is a pair.

returns

a pair of collections, containing the first, respectively second half of each element pair of this collection.

Definition Classes
GenericTraversableTemplate
168. #### def unzip3[A1, A2, A3](implicit asTriple: ((A, Set[B])) ⇒ (A1, A2, A3)): (Iterable[A1], Iterable[A2], Iterable[A3])

Converts this collection of triples into three collections of the first, second, and third element of each triple.

Converts this collection of triples into three collections of the first, second, and third element of each triple.

val xs = CC(
(1, "one", '1'),
(2, "two", '2'),
(3, "three", '3')).unzip3
// xs == (CC(1, 2, 3),
//        CC(one, two, three),
//        CC(1, 2, 3))
A1

the type of the first member of the element triples

A2

the type of the second member of the element triples

A3

the type of the third member of the element triples

asTriple

an implicit conversion which asserts that the element type of this collection is a triple.

returns

a triple of collections, containing the first, second, respectively third member of each element triple of this collection.

Definition Classes
GenericTraversableTemplate
169. #### def update(key: A, value: Set[B]): Unit

Adds a new key/value pair to this map.

Adds a new key/value pair to this map. If the map already contains a mapping for the key, it will be overridden by the new value.

key

The key to update

value

The new value

Definition Classes
MapLike
170. #### def updated[B1 >: Set[B]](key: A, value: B1): Map[A, B1]

Creates a new map consisting of all key/value pairs of the current map plus a new pair of a given key and value.

Creates a new map consisting of all key/value pairs of the current map plus a new pair of a given key and value.

B1

the type of the added value

key

value

The new value

returns

A fresh immutable map with the binding from key to value added to this map.

Definition Classes
MapLikeMapLike
171. #### def values: collection.Iterable[Set[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
MapLikeGenMapLike
Annotations
@migration
Migration

(Changed in version 2.8.0) values returns Iterable[B] rather than Iterator[B].

172. #### def valuesIterator: Iterator[Set[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
MapLikeGenMapLike
173. #### def view(from: Int, until: Int): IterableView[(A, Set[B]), Map[A, Set[B]]]

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
IterableLikeTraversableLike
174. #### def view: IterableView[(A, Set[B]), Map[A, Set[B]]]

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
IterableLikeTraversableLike
175. #### final def wait(): Unit

Definition Classes
AnyRef
Annotations
( ... )
176. #### final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
( ... )
177. #### final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
( ... )
178. #### def withDefault(d: (A) ⇒ Set[B]): Map[A, Set[B]]

The same map with a given default function.

The same map with a given default function.

Invoking transformer methods (e.g. map) will not preserve the default value.

d

the function mapping keys to values, used for non-present keys

returns

a wrapper of the map with a default value

Definition Classes
Map
179. #### def withDefaultValue(d: Set[B]): Map[A, Set[B]]

The same map with a given default value.

The same map with a given default value.

Invoking transformer methods (e.g. map) will not preserve the default value.

d

default value used for non-present keys

returns

a wrapper of the map with a default value

Definition Classes
Map
180. #### def withFilter(p: ((A, Set[B])) ⇒ Boolean): FilterMonadic[(A, Set[B]), Map[A, Set[B]]]

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
181. #### def zip[B](that: GenIterable[B]): MultiMap[(A, B)]

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

[use case]

Returns a multimap formed from this multimap 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 multimap containing pairs consisting of corresponding elements of this multimap and that. The length of the returned collection is the minimum of the lengths of this multimap and that.

Definition Classes
IterableLikeGenIterableLike
Full Signature

182. #### def zipAll[B](that: collection.Iterable[B], thisElem: A, thatElem: B): MultiMap[(A, B)]

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

[use case]

Returns a multimap formed from this multimap 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 multimap is shorter than that.

thatElem

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

returns

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

Definition Classes
IterableLikeGenIterableLike
Full Signature

183. #### def zipWithIndex: MultiMap[(A, Int)]

[use case] Zips this multimap with its indices.

[use case]

Zips this multimap with its indices.

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

returns

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

Definition Classes
IterableLikeGenIterableLike
Full Signature

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

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

184. #### def →[B](y: B): (MultiMap[A, B], B)

Implicit information
This member is added by an implicit conversion from MultiMap[A, B] to ArrowAssoc[MultiMap[A, B]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

1. #### def +(other: String): String

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

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

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

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

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