object Stream extends SeqFactory[Stream] with Serializable
The object Stream provides helper functions to manipulate streams.
- Source
- Stream.scala
- Version
1.1 08/08/03
- Since
2.8
- Alphabetic
- By Inheritance
- Stream
- Serializable
- Serializable
- SeqFactory
- TraversableFactory
- GenericSeqCompanion
- GenSeqFactory
- GenTraversableFactory
- GenericCompanion
- AnyRef
- Any
- Hide All
- Show All
- Public
- All
Type Members
-
class
GenericCanBuildFrom
[A] extends CanBuildFrom[CC[_], A, CC[A]]
A generic implementation of the
CanBuildFromtrait, which forwards all calls toapply(from)to thegenericBuildermethod of collectionfrom, and which forwards all calls ofapply()to thenewBuildermethod of this factory.A generic implementation of the
CanBuildFromtrait, which forwards all calls toapply(from)to thegenericBuildermethod of collectionfrom, and which forwards all calls ofapply()to thenewBuildermethod of this factory.- Definition Classes
- GenTraversableFactory
-
type
Coll = Stream[_]
The underlying collection type with unknown element type
The underlying collection type with unknown element type
- Attributes
- protected[this]
- Definition Classes
- GenericCompanion
-
final
class
Cons
[+A] extends Stream[A]
A lazy cons cell, from which streams are built.
A lazy cons cell, from which streams are built.
- Annotations
- @SerialVersionUID()
-
class
ConsWrapper
[A] extends AnyRef
A wrapper class that adds
#::for cons and#:::for concat as operations to streams. -
class
StreamBuilder
[A] extends LazyBuilder[A, Stream[A]]
A builder for streams
A builder for streams
- Note
This builder is lazy only in the sense that it does not go downs the spine of traversables that are added as a whole. If more laziness can be achieved, this builder should be bypassed.
-
class
StreamCanBuildFrom
[A] extends GenericCanBuildFrom[A]
The factory for streams.
The factory for streams.
- Note
Methods such as map/flatMap will not invoke the
Builderfactory, but will return a new stream directly, to preserve laziness. The new stream is then cast to the factory's result type. This means that every CanBuildFrom that takes a Stream as its From type parameter must yield a stream as its result parameter. If that assumption is broken, cast errors might result.
Value Members
-
final
def
!=(arg0: Any): Boolean
Test two objects for inequality.
Test two objects for inequality.
- returns
trueif !(this == that), false otherwise.
- Definition Classes
- AnyRef → Any
-
final
def
##(): Int
Equivalent to
x.hashCodeexcept for boxed numeric types andnull.Equivalent to
x.hashCodeexcept for boxed numeric types andnull. 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. Fornullreturns a hashcode wherenull.hashCodethrows aNullPointerException.- returns
a hash value consistent with ==
- Definition Classes
- AnyRef → Any
-
final
def
==(arg0: Any): Boolean
The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).The expression
x == thatis equivalent toif (x eq null) that eq null else x.equals(that).- returns
trueif the receiver object is equivalent to the argument;falseotherwise.
- Definition Classes
- AnyRef → Any
-
def
ReusableCBF: GenericCanBuildFrom[Nothing]
- Definition Classes
- GenTraversableFactory
-
def
apply[A](xs: A*): Stream[A]
A stream consisting of given elements
A stream consisting of given elements
- A
the type of the collection's elements
- returns
a new collection with elements
elems
- Definition Classes
- Stream → GenericCompanion
-
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 aClassCastExceptionat runtime, while the expressionList(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
ClassCastExceptionif the receiver object is not an instance of the erasure of typeT0.
- implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, Stream[A]]
-
def
clone(): AnyRef
Create a copy of the receiver object.
-
def
concat[A](xss: collection.Traversable[A]*): Stream[A]
Concatenates all argument collections into a single collection.
Concatenates all argument collections into a single collection.
- xss
the collections that are to be concatenated.
- returns
the concatenation of all the collections.
- Definition Classes
- GenTraversableFactory
-
implicit
def
consWrapper[A](stream: ⇒ Stream[A]): ConsWrapper[A]
A wrapper method that adds
#::for cons and#:::for concat as operations to streams. -
def
continually[A](elem: ⇒ A): Stream[A]
Create an infinite stream containing the given element expression (which is computed for each occurrence).
Create an infinite stream containing the given element expression (which is computed for each occurrence).
- elem
the element composing the resulting stream
- returns
the stream containing an infinite number of elem
-
def
empty[A]: Stream[A]
The empty stream
-
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
eqmethod implements an equivalence relation on non-null instances ofAnyRef, and has three additional properties:- It is consistent: for any non-null instances
xandyof typeAnyRef, multiple invocations ofx.eq(y)consistently returnstrueor consistently returnsfalse. - For any non-null instance
xof typeAnyRef,x.eq(null)andnull.eq(x)returnsfalse. null.eq(null)returnstrue.
When overriding the
equalsorhashCodemethods, 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
trueif the argument is a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
- It is consistent: for any non-null instances
-
def
equals(arg0: Any): Boolean
The equality method for reference types.
-
def
fill[A](n: Int)(elem: ⇒ A): Stream[A]
Produces a collection containing the results of some element computation a number of times.
Produces a collection containing the results of some element computation a number of times.
- n
the number of elements contained in the collection.
- elem
the element computation
- returns
A collection that contains the results of
nevaluations ofelem.
- Definition Classes
- Stream → GenTraversableFactory
-
def
fill[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(elem: ⇒ A): Stream[Stream[Stream[Stream[Stream[A]]]]]
Produces a five-dimensional collection containing the results of some element computation a number of times.
Produces a five-dimensional collection containing the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3nd dimension
- n4
the number of elements in the 4th dimension
- n5
the number of elements in the 5th dimension
- elem
the element computation
- returns
A collection that contains the results of
n1 x n2 x n3 x n4 x n5evaluations ofelem.
- Definition Classes
- GenTraversableFactory
-
def
fill[A](n1: Int, n2: Int, n3: Int, n4: Int)(elem: ⇒ A): Stream[Stream[Stream[Stream[A]]]]
Produces a four-dimensional collection containing the results of some element computation a number of times.
Produces a four-dimensional collection containing the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3nd dimension
- n4
the number of elements in the 4th dimension
- elem
the element computation
- returns
A collection that contains the results of
n1 x n2 x n3 x n4evaluations ofelem.
- Definition Classes
- GenTraversableFactory
-
def
fill[A](n1: Int, n2: Int, n3: Int)(elem: ⇒ A): Stream[Stream[Stream[A]]]
Produces a three-dimensional collection containing the results of some element computation a number of times.
Produces a three-dimensional collection containing the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3nd dimension
- elem
the element computation
- returns
A collection that contains the results of
n1 x n2 x n3evaluations ofelem.
- Definition Classes
- GenTraversableFactory
-
def
fill[A](n1: Int, n2: Int)(elem: ⇒ A): Stream[Stream[A]]
Produces a two-dimensional collection containing the results of some element computation a number of times.
Produces a two-dimensional collection containing the results of some element computation a number of times.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- elem
the element computation
- returns
A collection that contains the results of
n1 x n2evaluations ofelem.
- Definition Classes
- GenTraversableFactory
-
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
finalizemethod is invoked, as well as the interaction betweenfinalizeand non-local returns and exceptions, are all platform dependent. -
def
from(start: Int): Stream[Int]
Create an infinite stream starting at
startand incrementing by1.Create an infinite stream starting at
startand incrementing by1.- start
the start value of the stream
- returns
the stream starting at value
start.
-
def
from(start: Int, step: Int): Stream[Int]
Create an infinite stream starting at
startand incrementing by stepstep.Create an infinite stream starting at
startand incrementing by stepstep.- start
the start value of the stream
- step
the increment value of the stream
- returns
the stream starting at value
start.
-
final
def
getClass(): Class[_]
Returns the runtime class representation of the object.
Returns the runtime class representation of the object.
- returns
a class object corresponding to the runtime type of the receiver.
- Definition Classes
- AnyRef → Any
-
def
hashCode(): Int
The hashCode method for reference types.
-
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 returnfalse, while the expressionList(1).isInstanceOf[List[String]]will returntrue. 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
trueif the receiver object is an instance of erasure of typeT0;falseotherwise.
- Definition Classes
- Any
-
def
iterate[A](start: A, len: Int)(f: (A) ⇒ A): Stream[A]
Produces a collection containing repeated applications of a function to a start value.
Produces a collection containing repeated applications of a function to a start value.
- start
the start value of the collection
- len
the number of elements contained in the collection
- f
the function that's repeatedly applied
- returns
a collection with
lenvalues in the sequencestart, f(start), f(f(start)), ...
- Definition Classes
- Stream → GenTraversableFactory
-
def
iterate[A](start: A)(f: (A) ⇒ A): Stream[A]
An infinite stream that repeatedly applies a given function to a start value.
An infinite stream that repeatedly applies a given function to a start value.
- start
the start value of the stream
- f
the function that's repeatedly applied
- returns
the stream returning the infinite sequence of values
start, f(start), f(f(start)), ...
-
final
def
ne(arg0: AnyRef): Boolean
Equivalent to
!(this eq that).Equivalent to
!(this eq that).- returns
trueif the argument is not a reference to the receiver object;falseotherwise.
- Definition Classes
- AnyRef
-
def
newBuilder[A]: Builder[A, Stream[A]]
Creates a new builder for a stream
Creates a new builder for a stream
- A
the type of the collection's elements
- Definition Classes
- Stream → GenericCompanion
-
final
def
notify(): Unit
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Note
not specified by SLS as a member of AnyRef
-
final
def
notifyAll(): Unit
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
- Definition Classes
- AnyRef
- Note
not specified by SLS as a member of AnyRef
-
def
range[T](start: T, end: T, step: T)(implicit arg0: Integral[T]): Stream[T]
Produces a collection containing equally spaced values in some integer interval.
Produces a collection containing equally spaced values in some integer interval.
- start
the start value of the collection
- end
the end value of the collection (the first value NOT contained)
- step
the difference between successive elements of the collection (must be positive or negative)
- returns
a collection with values
start, start + step, ...up to, but excludingend
- Definition Classes
- Stream → GenTraversableFactory
-
def
range[T](start: T, end: T)(implicit arg0: Integral[T]): Stream[T]
Produces a collection containing a sequence of increasing of integers.
Produces a collection containing a sequence of increasing of integers.
- start
the first element of the collection
- end
the end value of the collection (the first value NOT contained)
- returns
a collection with values
start, start + 1, ..., end - 1
- Definition Classes
- GenTraversableFactory
-
final
def
synchronized[T0](arg0: ⇒ T0): T0
- Definition Classes
- AnyRef
-
def
tabulate[A](n: Int)(f: (Int) ⇒ A): Stream[A]
Produces a collection containing values of a given function over a range of integer values starting from 0.
Produces a collection containing values of a given function over a range of integer values starting from 0.
- n
The number of elements in the collection
- f
The function computing element values
- returns
A collection consisting of elements
f(0), ..., f(n -1)
- Definition Classes
- Stream → GenTraversableFactory
-
def
tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int, n5: Int)(f: (Int, Int, Int, Int, Int) ⇒ A): Stream[Stream[Stream[Stream[Stream[A]]]]]
Produces a five-dimensional collection containing values of a given function over ranges of integer values starting from 0.
Produces a five-dimensional collection containing values of a given function over ranges of integer values starting from 0.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3nd dimension
- n4
the number of elements in the 4th dimension
- n5
the number of elements in the 5th dimension
- f
The function computing element values
- returns
A collection consisting of elements
f(i1, i2, i3, i4, i5)for0 <= i1 < n1,0 <= i2 < n2,0 <= i3 < n3,0 <= i4 < n4, and0 <= i5 < n5.
- Definition Classes
- GenTraversableFactory
-
def
tabulate[A](n1: Int, n2: Int, n3: Int, n4: Int)(f: (Int, Int, Int, Int) ⇒ A): Stream[Stream[Stream[Stream[A]]]]
Produces a four-dimensional collection containing values of a given function over ranges of integer values starting from 0.
Produces a four-dimensional collection containing values of a given function over ranges of integer values starting from 0.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3nd dimension
- n4
the number of elements in the 4th dimension
- f
The function computing element values
- returns
A collection consisting of elements
f(i1, i2, i3, i4)for0 <= i1 < n1,0 <= i2 < n2,0 <= i3 < n3, and0 <= i4 < n4.
- Definition Classes
- GenTraversableFactory
-
def
tabulate[A](n1: Int, n2: Int, n3: Int)(f: (Int, Int, Int) ⇒ A): Stream[Stream[Stream[A]]]
Produces a three-dimensional collection containing values of a given function over ranges of integer values starting from 0.
Produces a three-dimensional collection containing values of a given function over ranges of integer values starting from 0.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- n3
the number of elements in the 3nd dimension
- f
The function computing element values
- returns
A collection consisting of elements
f(i1, i2, i3)for0 <= i1 < n1,0 <= i2 < n2, and0 <= i3 < n3.
- Definition Classes
- GenTraversableFactory
-
def
tabulate[A](n1: Int, n2: Int)(f: (Int, Int) ⇒ A): Stream[Stream[A]]
Produces a two-dimensional collection containing values of a given function over ranges of integer values starting from 0.
Produces a two-dimensional collection containing values of a given function over ranges of integer values starting from 0.
- n1
the number of elements in the 1st dimension
- n2
the number of elements in the 2nd dimension
- f
The function computing element values
- returns
A collection consisting of elements
f(i1, i2)for0 <= i1 < n1and0 <= i2 < n2.
- Definition Classes
- GenTraversableFactory
-
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
- AnyRef → Any
-
def
unapplySeq[A](x: Stream[A]): Some[Stream[A]]
This method is called in a pattern match { case Seq(...) => }.
This method is called in a pattern match { case Seq(...) => }.
- x
the selector value
- returns
sequence wrapped in an option, if this is a Seq, otherwise none
- Definition Classes
- SeqFactory
-
final
def
wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
final
def
wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws( ... )
-
object
#::
An extractor that allows to pattern match streams with
#::. - object Empty extends Stream[Nothing]
-
object
cons
An alternative way of building and matching Streams using Stream.cons(hd, tl).
This is the documentation for the Scala standard library.
Package structure
The scala package contains core types like
Int,Float,ArrayorOptionwhich are accessible in all Scala compilation units without explicit qualification or imports.Notable packages include:
scala.collectionand its sub-packages contain Scala's collections frameworkscala.collection.immutable- Immutable, sequential data-structures such asVector,List,Range,HashMaporHashSetscala.collection.mutable- Mutable, sequential data-structures such asArrayBuffer,StringBuilder,HashMaporHashSetscala.collection.concurrent- Mutable, concurrent data-structures such asTrieMapscala.collection.parallel.immutable- Immutable, parallel data-structures such asParVector,ParRange,ParHashMaporParHashSetscala.collection.parallel.mutable- Mutable, parallel data-structures such asParArray,ParHashMap,ParTrieMaporParHashSetscala.concurrent- Primitives for concurrent programming such asFuturesandPromisesscala.io- Input and output operationsscala.math- Basic math functions and additional numeric types likeBigIntandBigDecimalscala.sys- Interaction with other processes and the operating systemscala.util.matching- Regular expressionsOther 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.Predefobject are always in scope by default.Some of these identifiers are type aliases provided as shortcuts to commonly used classes. For example,
Listis an alias forscala.collection.immutable.List.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
Stringis an alias forjava.lang.String.