Java HashSet equals()用法及代碼示例

java.util.HashSet類的equals()方法用於驗證Object與HashSet的相等性並進行比較。僅當兩個HashSet包含相同順序的相同元素時，列表才返回true。

用法:

public boolean equals(Object o)

參數：此方法將對象o作為要與該集合相等性進行比較的參數。

返回值：如果指定對象等於此集合，則此方法返回true。

以下示例說明了equals()方法。

示例1:

// Java program to demonstrate equals() 
// method of HashSet 
  
import java.util.*; 
  
public class GFG { 
    public static void main(String[] argv) 
    { 
  
        // Creating object of HashSet<String> 
        HashSet<String> 
            arrset1 = new HashSet<String>(); 
  
        // Populating arrset1 
        arrset1.add("A"); 
        arrset1.add("B"); 
        arrset1.add("C"); 
        arrset1.add("D"); 
        arrset1.add("E"); 
  
        // print arrset1 
        System.out.println("First HashSet: "
                           + arrset1); 
  
        // Creating another object of HashSet<String> 
        HashSet<String> 
            arrset2 = new HashSet<String>(); 
  
        // Populating arrset2 
        arrset2.add("A"); 
        arrset2.add("B"); 
        arrset2.add("C"); 
        arrset2.add("D"); 
        arrset2.add("E"); 
  
        // print arrset2 
        System.out.println("Second HashSet: "
                           + arrset2); 
  
        // comparing first HashSet to another 
        // using equals() method 
        boolean value 
            = arrset1.equals(arrset2); 
  
        // print the value 
        System.out.println("Are both set equal: "
                           + value); 
    } 
}

輸出：

First HashSet: [A, B, C, D, E]
Second HashSet: [A, B, C, D, E]
Are both set equal: true

示例2:

// Java program to demonstrate equals() 
// method of HashSet 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) 
    { 
  
        // Creating object of HashSet 
        HashSet<Integer> 
            arrset1 = new HashSet<Integer>(); 
  
        // Populating arrset1 
        arrset1.add(10); 
        arrset1.add(20); 
        arrset1.add(30); 
        arrset1.add(40); 
        arrset1.add(50); 
  
        // print arrset1 
        System.out.println("First HashSet: "
                           + arrset1); 
  
        // Creating another object of HashSet 
        HashSet<Integer> 
            arrset2 = new HashSet<Integer>(); 
  
        // Populating arrset2 
        arrset2.add(10); 
        arrset2.add(20); 
        arrset2.add(30); 
  
        // print arrset2 
        System.out.println("Second HashSet: "
                           + arrset2); 
  
        // comparing first HashSet to another 
        // using equals() method 
        boolean value = arrset1.equals(arrset2); 
  
        // print the value 
        System.out.println("Are both set equal: "
                           + value); 
    } 
}

輸出：

First HashSet: [50, 20, 40, 10, 30]
Second HashSet: [20, 10, 30]
Are both set equal: false

相關用法

注：本文由純淨天空篩選整理自Code_r大神的英文原創作品 HashSet equals() method in Java with Example。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。