Java HashSet remove() 方法

2024年12月16日 | 2 分钟阅读

remove() 是 Java HashSet 类的一个方法，用于从该集合中移除指定的元素（如果存在）。

语法

以下是 remove() 方法的声明：

参数

参数	描述	必需/可选
o	它是将被移除到此集合的那个对象，如果存在的话。	必需

返回值

如果集合包含指定的元素，则 remove() 方法返回 true。

异常

不适用

兼容版本

Java 1.2 及以上版本

示例 1

import java.util.*;
public class HashSetRemoveExample1 {
	public static void main(String[] args) {
		HashSet<String> set=new HashSet<String>();  
		set.add("Ravi");  
		set.add("Vijay");  
		set.add("Aman");  
		set.add("Ajay");  
		//Display HashSet
            System.out.println("HashSet: " + set); 
            //Remove elements using remove() method
            set.remove("Vijay");
            // Displaying the HashSet after removal
            System.out.println("HashSet after removing elements: " + set);
	}
}

输出

HashSet: [Vijay, Ravi, Aman, Ajay]
HashSet after removing elements: [Ravi, Aman, Ajay]

示例 2

import java.util.*;
public class HashSetRemoveExample2 {
	public static void main(String[] args) {
		HashSet<Integer> hashSetObject = new HashSet <>();
		hashSetObject.add(45);
		hashSetObject.add(67);
		hashSetObject.add(98);
		hashSetObject.add(24);
		//Display HashSet
            System.out.println("HashSet: " + hashSetObject); 
            //Remove elements using remove() method
            hashSetObject.remove(98);
            hashSetObject.remove(24);
            //Displaying the HashSet after removal
          System.out.println("HashSet after removing elements: " + hashSetObject);
	}
}

输出

HashSet: [98, 67, 24, 45]
HashSet after removing elements: [67, 45]

示例 3

import java.util.*;  
class Book {  
	int id;  
	String name,author,publisher;  
	int quantity;  
	public Book(int id, String name, String author, String publisher, int quantity) {  
		this.id = id;  
		this.name = name;  
		this.author = author;  
		this.publisher = publisher;  
		this.quantity = quantity;  
	}  
}  
public class HashSetRemoveExample3 {  
	public static void main(String[] args) {  
		HashSet<Book> set=new HashSet<Book>();  
		//Creating Books  
		Book b1=new Book(101,"Let us C","Yashwant Kanetkar","BPB",8);  
		Book b2=new Book(102,"Data Communications & Networking","Forouzan","Mc Graw Hill",4);  
		Book b3=new Book(103,"Operating System","Galvin","Wiley",6);  
		//Adding Books to HashSet  
		set.add(b1);  
		set.add(b2);  
		set.add(b3);  
		//Traversing HashSet  
		for(Book b:set){  
			System.out.println(b.id+" "+b.name+" "+b.author+" "+b.publisher+" "+b.quantity);  
		} 
		//Removing elements to HashSet
		set.remove(b2); 
		System.out.println("Books after remove method:");
		for(Book b:set){  
			System.out.println(b.id+" "+b.name+" "+b.author+" "+b.publisher+" "+b.quantity);  
		} 
	}  
}  

输出

103 Operating System Galvin Wiley 6
101 Let us C Yashwant Kanetkar BPB 8
102 Data Communications & Networking Forouzan Mc Graw Hill 4
Books after remove method:
103 Operating System Galvin Wiley 6
101 Let us C Yashwant Kanetkar BPB 8

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Java HashSet remove() 方法

语法

参数

返回值

异常

兼容版本

示例 1

示例 2

示例 3

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