The following example demonstrates how to use collection.add() of the Collections class to add data and use collection.size() to calculate the length of the collection:
/* author by w3cschool.cc Main.java */import java.util.*;public class Main { public static void main(String [] args) { System.out.println( "集合实例!\n" ); int size; HashSet collection = new HashSet (); String str1 = "Yellow", str2 = "White", str3 = "Green", str4 = "Blue"; Iterator iterator; collection.add(str1); collection.add(str2); collection.add(str3); collection.add(str4); System.out.print("集合数据: "); iterator = collection.iterator(); while (iterator.hasNext()){ System.out.print(iterator.next() + " "); } System.out.println(); size = collection.size(); if (collection.isEmpty()){ System.out.println("集合是空的"); } else{ System.out.println( "集合长度: " + size); } System.out.println(); }}
The output of the above code is:
集合实例! 集合数据: White Yellow Blue Green 集合长度: 4
The above is the Java example - collection length content. For more related content, please pay attention to the PHP Chinese website (m.sbmmt.com)!