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
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- Public
- All
Type Members
-
class
GenericCanBuildFrom
[A] extends CanBuildFrom[CC[_], A, CC[A]]
A generic implementation of the
CanBuildFrom
trait, which forwards all calls toapply(from)
to thegenericBuilder
method of collectionfrom
, and which forwards all calls ofapply()
to thenewBuilder
method of this factory.A generic implementation of the
CanBuildFrom
trait, which forwards all calls toapply(from)
to thegenericBuilder
method of collectionfrom
, and which forwards all calls ofapply()
to thenewBuilder
method of this factory.- Definition Classes
- GenTraversableFactory
-
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
Builder
factory, 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
-
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
- implicit def canBuildFrom[A]: CanBuildFrom[Coll, A, Stream[A]]
-
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
-
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
n
evaluations 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 n5
evaluations 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 n4
evaluations 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 n3
evaluations 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 n2
evaluations ofelem
.
- Definition Classes
- GenTraversableFactory
-
def
from(start: Int): Stream[Int]
Create an infinite stream starting at
start
and incrementing by1
.Create an infinite stream starting at
start
and 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
start
and incrementing by stepstep
.Create an infinite stream starting at
start
and incrementing by stepstep
.- start
the start value of the stream
- step
the increment value of the stream
- returns
the stream starting at value
start
.
-
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
len
values 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)), ...
-
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
-
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
-
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 < n1
and0 <= i2 < n2
.
- Definition Classes
- GenTraversableFactory
-
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
-
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
,Array
orOption
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 frameworkscala.collection.immutable
- Immutable, sequential data-structures such asVector
,List
,Range
,HashMap
orHashSet
scala.collection.mutable
- Mutable, sequential data-structures such asArrayBuffer
,StringBuilder
,HashMap
orHashSet
scala.collection.concurrent
- Mutable, concurrent data-structures such asTrieMap
scala.collection.parallel.immutable
- Immutable, parallel data-structures such asParVector
,ParRange
,ParHashMap
orParHashSet
scala.collection.parallel.mutable
- Mutable, parallel data-structures such asParArray
,ParHashMap
,ParTrieMap
orParHashSet
scala.concurrent
- Primitives for concurrent programming such asFutures
andPromises
scala.io
- Input and output operationsscala.math
- Basic math functions and additional numeric types likeBigInt
andBigDecimal
scala.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, including an example implementation of a JSON parser (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 forscala.collection.immutable.List
.Other aliases refer to classes provided by the underlying platform. For example, on the JVM,
String
is an alias forjava.lang.String
.