Java streams counting() method with examples
Last Updated :
06 Dec, 2018
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In Java 8, there is predefined counting() method returned by Collectors class counting() method to count the number of elements in a Stream.
Syntax :
public static Collector counting() Where, output is a Collector, acting on a Stream of elements of type T, with its finisher returning the ‘collected’ value of type Long. It is a terminal operation which returns the total count of elements in the stream which reach the collect() method after undergoing various pipelined stream operations such as filtering.
Example 1 : To count the elements in stream of Integers.
// Java code to count number of elements // in stream import java.util.stream.Stream; import java.util.stream.Collectors; class counting { public static void main(String[] args) { // creating stream of integers Stream<Integer> i = Stream.of(1, 2, 3, 4, 5, 6); // counting number of integer in stream long count_int = i.collect(Collectors.counting()); System.out.println(count_int); } } |
Output:
6
Example 2 : To count the elements in stream of String.
// JAVA code to count number of elements in stream import java.util.stream.Stream; import java.util.stream.Collectors; class counting { public static void main(String[] args) { // creating stream of strings Stream<String> s = Stream.of("Akash","Harsh", "Shubham","Nishant","Pratik"); // counting number of strings in stream long count_string = s.collect(Collectors.counting()); System.out.println(count_string); } } |
Output:
5
