IntStream peek() is a method in java.util.stream.IntStream. The function returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.
Syntax :
IntStream peek(IntConsumer action) Where, IntStream is a sequence of primitive int-valued elements and the function returns a parallel IntStream and IntConsumer represents an operation that accepts a single int-valued argument.
Example 1 : Performing sum on a stream of given range.
// Java code for IntStream peek()// where the action performed is to get// sum of all elements in given rangeimport java.util.*;import java.util.stream.IntStream;  class GFG {          // Driver code    public static void main(String[] args) {          // Creating a stream of integers    IntStream stream = IntStream.range(2, 10);          // performing action sum on elements of     // given range and storing the result in sum    int sum = stream.peek(System.out::println).sum();          // Displaying the result of action performed             System.out.println("sum is : " + sum);}} |
Output :
2 3 4 5 6 7 8 9 sum is : 44
Example 2 : Performing count operation on a stream of given range.
// Java code for IntStream peek()// where the action performed is to get// count of all elements in given rangeimport java.util.*;import java.util.stream.IntStream;  class GFG {          // Driver code    public static void main(String[] args) {          // Creating a stream of integers    IntStream stream = IntStream.range(2, 10);          // performing action count on elements of     // given range and storing the result in Count    long Count = stream.peek(System.out::println).count();          // Displaying the result of action performed                         System.out.println("count : " + Count);}} |
Output :
2 3 4 5 6 7 8 9 count : 8
Example 3 : Performing Average operation on a stream of given range.
// Java code for IntStream peek()// where the action performed is to get// average of all elements in given rangeimport java.util.*;import java.util.OptionalDouble;import java.util.stream.IntStream;  class GFG {          // Driver code    public static void main(String[] args) {          // Creating a stream of integers    IntStream stream = IntStream.range(2, 10);      // performing action average on elements of     // given range and storing the result in avg    OptionalDouble avg = stream.peek(System.out::println)                        .average();          // If a value is present, isPresent()    // will return true, else -1 is displayed.    if(avg.isPresent())    {    System.out.println("Average is : " + avg.getAsDouble());    }    else    {    System.out.println("-1");     } }} |
Output :
2 3 4 5 6 7 8 9 Average is : 5.5
