Java Streams - Stream iterate(T seed, UnaryOperator f) example

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Stream iterate(T seed, UnaryOperator<T> f) creates an infinite Stream from iterative application of a function f to an initial element seed. The result Stream consists seed, f(seed), f(f(seed)), etc.

Syntax

iterate has the following syntax.

static <T> Stream<T> iterate(T seed,   UnaryOperator<T> f)

Example

The following example shows how to use iterate.

import java.util.stream.Stream;
//from   w  w  w  .j  a va  2s  . c o  m
public class Main {
  public static void main(String[] args) {
    Stream.iterate(1,n->n + 1)
          .limit(10)
          .forEach(System.out::println); 

  }
}

The code above generates the following result.

Example 2

Calculate fibonnaci with iterate and Stream

import java.util.stream.Stream;
//  ww w.  j a v  a 2s .c o m
public class Main {

  public static void main(String[] args) {
    // fibonnaci with iterate
    Stream.iterate(new int[]{0, 1}, t -> new int[]{t[1],t[0] + t[1]})
          .limit(10)
          .forEach(t -> System.out.println("(" + t[0] + ", " + t[1] + ")"));
  }

}

The code above generates the following result.

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