In order to count number of element in Set/HashSet , use size() method. Set.size() method returns the number of elements in this set (its cardinality).
Syntax :
public int size() {
}
Parameter : It does not take any parameter. Returns Value : It the number of elements in this set (its cardinality)
import java.util.HashSet;
import java.util.Set;
public class CountElement {
public static void main(String[] args) {
Set<String> hs = new HashSet<String>();
hs.add("java");
hs.add("php");
hs.add("html");
hs.add("javascript");
hs.add("mysql");
//print hashset
System.out.println("hashset = "+hs);
/*
* Returns the number of elements in set. If this set contains more than
* Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.
*/
System.out.println("Size of hashset = "+hs.size());
}
}
Output:
hashset = [javascript, php, html, java, mysql]
Size of hashset = 5