Scala Standard Library2.12.6 < Back
 

# Packages

-  package root

  This is the documentation for the Scala standard library.

  This is the documentation for the Scala standard library.

  #### Package structure

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

  Notable packages include:

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

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

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

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

  #### Automatic imports

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

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

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

  Definition Classes
    root
-  package scala

  Core Scala types.

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

  Definition Classes
    root
-  object Predef extends LowPriorityImplicits with DeprecatedPredef

  The `Predef` object provides definitions that are accessible in all Scala compilation units without explicit qualification.

  The `Predef` object provides definitions that are accessible in all Scala compilation units without explicit qualification.

  ##### Commonly Used Types

  Predef provides type aliases for types which are commonly used, such as the immutable collection types scala.collection.immutable.Map, scala.collection.immutable.Set, and the scala.collection.immutable.List constructors (scala.collection.immutable.:: and scala.collection.immutable.Nil).

  ##### Console Output

  For basic console output, `Predef` provides convenience methods print and println, which are aliases of the methods in the object scala.Console.

  ##### Assertions

  A set of `assert` functions are provided for use as a way to document and dynamically check invariants in code. Invocations of `assert` can be elided at compile time by providing the command line option `-Xdisable-assertions`, which raises `-Xelide-below` above `elidable.ASSERTION`, to the `scalac` command.

  Variants of `assert` intended for use with static analysis tools are also provided: `assume`, `require` and `ensuring`. `require` and `ensuring` are intended for use as a means of design-by-contract style specification of pre- and post-conditions on functions, with the intention that these specifications could be consumed by a static analysis tool. For instance,

      def addNaturals(nats: List[Int]): Int = {
        require(nats forall (_ >= 0), "List contains negative numbers")
        nats.foldLeft(0)(_ + _)
      } ensuring(_ >= 0)

  The declaration of `addNaturals` states that the list of integers passed should only contain natural numbers (i.e. non-negative), and that the result returned will also be natural. `require` is distinct from `assert` in that if the condition fails, then the caller of the function is to blame rather than a logical error having been made within `addNaturals` itself. `ensuring` is a form of `assert` that declares the guarantee the function is providing with regards to its return value.

  ##### Implicit Conversions

  A number of commonly applied implicit conversions are also defined here, and in the parent type scala.LowPriorityImplicits. Implicit conversions are provided for the "widening" of numeric values, for instance, converting a Short value to a Long value as required, and to add additional higher-order functions to Array values. These are described in more detail in the documentation of scala.Array.

  Definition Classes
    scala
- <:<
- =:=
- ArrayCharSequence
- ArrowAssoc
- DummyImplicit
- Ensuring
- Pair
- RichException
- SeqCharSequence
- StringFormat
- Triple
- any2stringadd

c

scala.Predef

# ArrayCharSequence 

###

#### implicit final class ArrayCharSequence extends CharSequence

Source
  Predef.scala

Linear Supertypes
CharSequence, AnyRef, Any
 
Ordering

1. Alphabetic
2. By Inheritance

Inherited

1. ArrayCharSequence
2. CharSequence
3. AnyRef
4. Any

Implicitly

1. by any2stringadd
2. by StringFormat
3. by Ensuring
4. by ArrowAssoc
5. by any2stringadd
6. by StringFormat
7. by Ensuring
8. by ArrowAssoc

1. Hide All
2. Show All

Visibility

1. Public
2. All

### Instance Constructors

1.  new ArrayCharSequence(__arrayOfChars: Array[Char])

### Value Members

1.  final def !=(arg0: Any): Boolean

   Test two objects for inequality.

   Test two objects for inequality.

   returns

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

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

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

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

   returns

     a hash value consistent with ==

   Definition Classes
     AnyRef → Any
3.  final def ==(arg0: Any): Boolean

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

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

   returns

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

   Definition Classes
     AnyRef → Any
4.  final def asInstanceOf[T0]: T0

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

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

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

   returns

     the receiver object.

   Definition Classes
     Any
   Exceptions thrown

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

5.  def charAt(index: Int): Char
   Definition Classes
     ArrayCharSequence → CharSequence
6.  def chars(): IntStream
   Definition Classes
     CharSequence
7.  def clone(): AnyRef

   Create a copy of the receiver object.

   Create a copy of the receiver object.

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

   returns

     a copy of the receiver object.

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

     not specified by SLS as a member of AnyRef

8.  def codePoints(): IntStream
   Definition Classes
     CharSequence
9.  final def eq(arg0: AnyRef): Boolean

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

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

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

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

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

   returns

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

   Definition Classes
     AnyRef
10.  def equals(arg0: Any): Boolean

    The equality method for reference types.

    The equality method for reference types. Default implementation delegates to `eq`.

    See also `equals` in scala.Any.

    returns

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

    Definition Classes
      AnyRef → Any
11.  def finalize(): Unit

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

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

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

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

      not specified by SLS as a member of AnyRef

12.  final def getClass(): java.lang.Class[_]

    Returns the runtime class representation of the object.

    Returns the runtime class representation of the object.

    returns

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

    Definition Classes
      AnyRef → Any
    Annotations
      @native()
13.  def hashCode(): Int

    The hashCode method for reference types.

    The hashCode method for reference types. See hashCode in scala.Any.

    returns

      the hash code value for this object.

    Definition Classes
      AnyRef → Any
    Annotations
      @native()
14.  final def isInstanceOf[T0]: Boolean

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

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

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

    returns

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

    Definition Classes
      Any
15.  def length(): Int
    Definition Classes
      ArrayCharSequence → CharSequence
16.  final def ne(arg0: AnyRef): Boolean

    Equivalent to `!(this eq that)`.

    Equivalent to `!(this eq that)`.

    returns

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

    Definition Classes
      AnyRef
17.  final def notify(): Unit

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

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

    Definition Classes
      AnyRef
    Annotations
      @native()
    Note

      not specified by SLS as a member of AnyRef

18.  final def notifyAll(): Unit

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

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

    Definition Classes
      AnyRef
    Annotations
      @native()
    Note

      not specified by SLS as a member of AnyRef

19.  def subSequence(start: Int, end: Int): CharSequence
    Definition Classes
      ArrayCharSequence → CharSequence
20.  final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
      AnyRef
21.  def toString(): String

    Creates a String representation of this object.

    Creates a String representation of this object. The default representation is platform dependent. On the java platform it is the concatenation of the class name, "@", and the object's hashcode in hexadecimal.

    returns

      a String representation of the object.

    Definition Classes
      ArrayCharSequence → CharSequence → AnyRef → Any
22.  final def wait(): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
23.  final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
      AnyRef
    Annotations
      @throws( ... )
24.  final def wait(arg0: Long): Unit
    Definition Classes
      AnyRef
    Annotations
      @native() @throws( ... )

### Shadowed Implicit Value Members

1.  def +(other: String): String
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to any2stringadd[ArrayCharSequence] performed by method any2stringadd in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: any2stringadd[ArrayCharSequence]).+(other)

   Definition Classes
     any2stringadd
2.  def +(other: String): String
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to any2stringadd[ArrayCharSequence] performed by method any2stringadd in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: any2stringadd[ArrayCharSequence]).+(other)

   Definition Classes
     any2stringadd
3.  def ->[B](y: B): (ArrayCharSequence, B)
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to ArrowAssoc[ArrayCharSequence] performed by method ArrowAssoc in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: ArrowAssoc[ArrayCharSequence]).->(y)

   Definition Classes
     ArrowAssoc
   Annotations
     @inline()
4.  def ->[B](y: B): (ArrayCharSequence, B)
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to ArrowAssoc[ArrayCharSequence] performed by method ArrowAssoc in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: ArrowAssoc[ArrayCharSequence]).->(y)

   Definition Classes
     ArrowAssoc
   Annotations
     @inline()
5.  def ensuring(cond: (ArrayCharSequence) ⇒ Boolean, msg: ⇒ Any): ArrayCharSequence
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond, msg)

   Definition Classes
     Ensuring
6.  def ensuring(cond: (ArrayCharSequence) ⇒ Boolean): ArrayCharSequence
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond)

   Definition Classes
     Ensuring
7.  def ensuring(cond: Boolean, msg: ⇒ Any): ArrayCharSequence
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond, msg)

   Definition Classes
     Ensuring
8.  def ensuring(cond: Boolean): ArrayCharSequence
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond)

   Definition Classes
     Ensuring
9.  def ensuring(cond: (ArrayCharSequence) ⇒ Boolean, msg: ⇒ Any): ArrayCharSequence
   Implicit
     This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
   Shadowing
     This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
     To access this member you can use a type ascription:

         (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond, msg)

   Definition Classes
     Ensuring
10.  def ensuring(cond: (ArrayCharSequence) ⇒ Boolean): ArrayCharSequence
    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond)

    Definition Classes
      Ensuring
11.  def ensuring(cond: Boolean, msg: ⇒ Any): ArrayCharSequence
    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond, msg)

    Definition Classes
      Ensuring
12.  def ensuring(cond: Boolean): ArrayCharSequence
    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to Ensuring[ArrayCharSequence] performed by method Ensuring in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: Ensuring[ArrayCharSequence]).ensuring(cond)

    Definition Classes
      Ensuring
13.  def formatted(fmtstr: String): String

    Returns string formatted according to given `format` string.

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

    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to StringFormat[ArrayCharSequence] performed by method StringFormat in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: StringFormat[ArrayCharSequence]).formatted(fmtstr)

    Definition Classes
      StringFormat
    Annotations
      @inline()
14.  def formatted(fmtstr: String): String

    Returns string formatted according to given `format` string.

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

    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to StringFormat[ArrayCharSequence] performed by method StringFormat in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: StringFormat[ArrayCharSequence]).formatted(fmtstr)

    Definition Classes
      StringFormat
    Annotations
      @inline()
15.  def →[B](y: B): (ArrayCharSequence, B)
    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to ArrowAssoc[ArrayCharSequence] performed by method ArrowAssoc in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: ArrowAssoc[ArrayCharSequence]).→(y)

    Definition Classes
      ArrowAssoc
16.  def →[B](y: B): (ArrayCharSequence, B)
    Implicit
      This member is added by an implicit conversion from ArrayCharSequence to ArrowAssoc[ArrayCharSequence] performed by method ArrowAssoc in scala.Predef.
    Shadowing
      This implicitly inherited member is ambiguous. One or more implicitly inherited members have similar signatures, so calling this member may produce an ambiguous implicit conversion compiler error.
      To access this member you can use a type ascription:

          (arrayCharSequence: ArrowAssoc[ArrayCharSequence]).→(y)

    Definition Classes
      ArrowAssoc

### Deprecated Value Members

1.  val __arrayOfChars: Array[Char]
   Annotations
     @deprecated
   Deprecated

     (Since version 2.12.0) will be made private

### Inherited from CharSequence

### Inherited from AnyRef

### Inherited from Any

### Inherited by implicit conversion any2stringadd from ArrayCharSequence to any2stringadd[ArrayCharSequence]

### Inherited by implicit conversion StringFormat from ArrayCharSequence to StringFormat[ArrayCharSequence]

### Inherited by implicit conversion Ensuring from ArrayCharSequence to Ensuring[ArrayCharSequence]

### Inherited by implicit conversion ArrowAssoc from ArrayCharSequence to ArrowAssoc[ArrayCharSequence]

### Inherited by implicit conversion any2stringadd from ArrayCharSequence to any2stringadd[ArrayCharSequence]

### Inherited by implicit conversion StringFormat from ArrayCharSequence to StringFormat[ArrayCharSequence]

### Inherited by implicit conversion Ensuring from ArrayCharSequence to Ensuring[ArrayCharSequence]

### Inherited by implicit conversion ArrowAssoc from ArrayCharSequence to ArrowAssoc[ArrayCharSequence]

### Ungrouped