in scala
trait Stream

`abstract trait` Stream [a]
  `extends` java.lang.Object
  `with` scala.Seq[a]
  `with` scala.ScalaObject

  The class `Stream` implements lazy lists where elements are only evaluated when they are needed. Here is an example:

       object Main extends Application {

         def from(n: Int): Stream[Int] =
           Stream.cons(n, from(n + 1))

         def sieve(s: Stream[Int]): Stream[Int] =
           Stream.cons(s.head, sieve(s.tail filter { x => x % s.head != 0 }))

         def primes = sieve(from(2))

         primes take 10 print
       }

Author:
  Martin Odersky, Matthias Zenger
Version:
  1.1 08/08/03

Def Summary
`abstract` `protected` | `def` addDefinedElems (buf: scala.compat.StringBuilder, prefix: java.lang.String) : scala.compat.StringBuilder Write all elements of this string into given string builder
| `def` append [b >: a] (rest: => scala.Stream[b]) : scala.Stream[b] The stream resulting from the concatenation of thsi stream with the argument stream.
| `def` apply (n: scala.Int) : a Returns the `n`-th element of this stream. The first element (head of the stream) is at position 0.
`override` | `def` copyToArray [b >: a] (xs: scala.Array[b], start: scala.Int) : scala.Unit Fills the given array `xs` with the elements of this stream starting at position `start`.
`override` | `def` drop (n: scala.Int) : scala.Stream[a] Returns the stream without its `n` first elements. If the stream has less than `n` elements, the empty stream is returned.
`override` | `def` dropWhile (p: (a) => scala.Boolean) : scala.Stream[a] Returns the longest suffix of this stream whose first element does not satisfy the predicate `p`.
| `def` elements : scala.Iterator[a] An iterator returning the elements of this stream one by one.
`override` | `def` exists (p: (a) => scala.Boolean) : scala.Boolean Tests the existence in this stream of an element that satisfies the predicate `p`.
`override` | `def` filter (p: (a) => scala.Boolean) : scala.Stream[a] Returns all the elements of this stream that satisfy the predicate `p`. The order of the elements is preserved.
`override` | `def` flatMap [b] (f: (a) => scala.Iterable[b]) : scala.Stream[b] Applies the given function `f` to each element of this stream, then concatenates the results.
`override` | `def` foldLeft [b] (z: b)(f: (b, a) => b) : b Combines the elements of this stream together using the binary function `f`, from left to right, and starting with the value `z`.
`override` | `def` foldRight [b] (z: b)(f: (a, b) => b) : b Combines the elements of this stream together using the binary function `f`, from rigth to left, and starting with the value `z`.
`override` | `def` forall (p: (a) => scala.Boolean) : scala.Boolean Tests if the predicate `p` is satisfied by all elements in this stream.
`override` | `def` foreach (f: (a) => scala.Unit) : scala.Unit Apply the given function `f` to each element of this stream (while respecting the order of the elements).
`abstract` | `def` head : a The first element of this stream
| `def` init : scala.Stream[a] The stream without its last element.
`abstract` `override` | `def` isEmpty : scala.Boolean is this stream empty?
| `def` last : a Returns the last element of this stream.
| `def` length : scala.Int The length of this stream
`override` | `def` map [b] (f: (a) => b) : scala.Stream[b] Returns the stream resulting from applying the given function `f` to each element of this stream.
| `def` print (out: java.io.PrintStream) : scala.Unit
| `def` print (out: java.io.PrintStream, sep: java.lang.String) : scala.Unit
| `def` print (sep: java.lang.String) : scala.Unit Prints elements of this stream one by one, separated by `sep`
| `def` print : scala.Unit Prints elements of this stream one by one, separated by commas
`override` | `def` reverse : scala.Stream[a] A stream consisting of all elements of this stream in reverse order.
`abstract` | `def` tail : scala.Stream[a] A stream consisting of the remaining elements of this stream after the first one.
`override` | `def` take (n: scala.Int) : scala.Stream[a] Returns the `n` first elements of this stream, or else the whole stream, if it has less than `n` elements.
`override` | `def` takeWhile (p: (a) => scala.Boolean) : scala.Stream[a] Returns the longest prefix of this stream whose elements satisfy the predicate `p`.
`override` | `def` toString : java.lang.String Converts stream to string
| `def` zip [b] (that: scala.Stream[b]) : scala.Stream[scala.Tuple2[a, b]] Returns a stream formed from this stream and the specified stream `that` by associating each element of the former with the element at the same position in the latter. If one of the two streams is longer than the other, its remaining elements are ignored.
| `def` zipWithIndex : scala.Stream[scala.Tuple2[a, scala.Int]] Returns a stream that pairs each element of this stream with its index, counting from 0.

Def inherited from scala.Seq[a]
++ , concat, contains, copyToArray, drop, dropWhile, filter, flatMap, isDefinedAt, isEmpty, lastIndexOf, length, map, reverse, slice, stringPrefix, subseq, super$drop, super$dropWhile, super$filter, super$take, super$takeWhile, take, takeWhile, toArray, toString

Def Detail

`abstract protected def` addDefinedElems (buf: scala.compat.StringBuilder, prefix: java.lang.String): scala.compat.StringBuilder

  Write all elements of this string into given string builder

`def` append [b >: a](rest: => scala.Stream[b]): scala.Stream[b]

  The stream resulting from the concatenation of thsi stream with the argument stream.

Parameters:
  `rest -` The stream that gets appended to this stream

`def` apply (n: scala.Int): a

  Returns the `n`-th element of this stream. The first element (head of the stream) is at position 0.

Parameters:
  `n -` index of the element to return
Returns:
  the element at position `n` in this stream.
Throws:
  `Predef.NoSuchElementException -` if the stream is too short.

`override def` copyToArray [b >: a](xs: scala.Array[b], start: scala.Int): scala.Unit

  Fills the given array `xs` with the elements of this stream starting at position `start`.

Parameters:
  `xs -` the array to fill.
Parameters:
  `start -` starting index.
Precondition:
  the array must be large enough to hold all elements.

`override def` drop (n: scala.Int): scala.Stream[a]

  Returns the stream without its `n` first elements. If the stream has less than `n` elements, the empty stream is returned.

Parameters:
  `n -` the number of elements to drop.
Returns:
  the stream without its `n` first elements.

`override def` dropWhile (p: (a) => scala.Boolean): scala.Stream[a]

  Returns the longest suffix of this stream whose first element does not satisfy the predicate `p`.

Parameters:
  `p -` the test predicate.
Returns:
  the longest suffix of the stream whose first element does not satisfy the predicate `p`.

`def` elements : scala.Iterator[a]

  An iterator returning the elements of this stream one by one.

`override def` exists (p: (a) => scala.Boolean): scala.Boolean

  Tests the existence in this stream of an element that satisfies the predicate `p`.

Parameters:
  `p -` the test predicate.
Returns:
  `true` iff there exists an element in this stream that satisfies the predicate `p`.

`override def` filter (p: (a) => scala.Boolean): scala.Stream[a]

  Returns all the elements of this stream that satisfy the predicate `p`. The order of the elements is preserved.

Parameters:
  `p -` the predicate used to filter the stream.
Returns:
  the elements of this stream satisfying `p`.

`override def` flatMap [b](f: (a) => scala.Iterable[b]): scala.Stream[b]

  Applies the given function `f` to each element of this stream, then concatenates the results.

Parameters:
  `f -` the function to apply on each element.
Returns:
  `f(a0) ::: ... ::: f(an)` if this stream is `[a0, ..., an]`.

`override def` foldLeft [b](z: b)(f: (b, a) => b): b

  Combines the elements of this stream together using the binary function `f`, from left to right, and starting with the value `z`.

Returns:
  `f(... (f(f(z, a0), a1) ...), an)` if the stream is `[a0, a1, ..., an]`.

`override def` foldRight [b](z: b)(f: (a, b) => b): b

  Combines the elements of this stream together using the binary function `f`, from rigth to left, and starting with the value `z`.

Returns:
  `f(a0, f(a1, f(..., f(an, z)...)))` if the stream is `[a0, a1, ..., an]`.

`override def` forall (p: (a) => scala.Boolean): scala.Boolean

  Tests if the predicate `p` is satisfied by all elements in this stream.

Parameters:
  `p -` the test predicate.
Returns:
  `true` iff all elements of this stream satisfy the predicate `p`.

`override def` foreach (f: (a) => scala.Unit): scala.Unit

  Apply the given function `f` to each element of this stream (while respecting the order of the elements).

Parameters:
  `f -` the treatment to apply to each element.

`abstract def` head : a

  The first element of this stream

Throws:
  `Predef.NoSuchElementException -` if the stream is empty.

`def` init : scala.Stream[a]

  The stream without its last element.

Throws:
  `Predef.UnsupportedOperationException -` if the stream is empty.

`abstract override def` isEmpty : scala.Boolean

  is this stream empty?

`def` last : a

  Returns the last element of this stream.

Returns:
  the last element of the stream.
Throws:
  `Predef.NoSuchElementException -` if the stream is empty.

`def` length : scala.Int

  The length of this stream

`override def` map [b](f: (a) => b): scala.Stream[b]

  Returns the stream resulting from applying the given function `f` to each element of this stream.

Parameters:
  `f -` function to apply to each element.
Returns:
  `[f(a0), ..., f(an)]` if this stream is `[a0, ..., an]`.

`def` print (out: java.io.PrintStream): scala.Unit

`def` print (out: java.io.PrintStream, sep: java.lang.String): scala.Unit

`def` print (sep: java.lang.String): scala.Unit

  Prints elements of this stream one by one, separated by `sep`

Parameters:
  `sep -` The separator string printed between consecutive elements.

`def` print : scala.Unit

  Prints elements of this stream one by one, separated by commas

`override def` reverse : scala.Stream[a]

  A stream consisting of all elements of this stream in reverse order.

`abstract def` tail : scala.Stream[a]

  A stream consisting of the remaining elements of this stream after the first one.

Throws:
  `Predef.UnsupportedOperationException -` if the stream is empty.

`override def` take (n: scala.Int): scala.Stream[a]

  Returns the `n` first elements of this stream, or else the whole stream, if it has less than `n` elements.

Parameters:
  `n -` the number of elements to take.
Returns:
  the `n` first elements of this stream.

`override def` takeWhile (p: (a) => scala.Boolean): scala.Stream[a]

  Returns the longest prefix of this stream whose elements satisfy the predicate `p`.

Parameters:
  `p -` the test predicate.
Returns:
  the longest prefix of this stream whose elements satisfy the predicate `p`.

`override def` toString : java.lang.String

  Converts stream to string

`def` zip [b](that: scala.Stream[b]): scala.Stream[scala.Tuple2[a, b]]

  Returns a stream formed from this stream and the specified stream `that` by associating each element of the former with the element at the same position in the latter. If one of the two streams is longer than the other, its remaining elements are ignored.

Returns:
  `Stream({a0,b0}, ..., {amin(m,n),bmin(m,n))}` when `Stream(a0, ..., am) zip Stream(b0, ..., bn)` is invoked.

`def` zipWithIndex : scala.Stream[scala.Tuple2[a, scala.Int]]

  Returns a stream that pairs each element of this stream with its index, counting from 0.

Returns:
  the stream `Stream({a0,0}, {a0,1},...)` where `ai` are the elements of this stream.