Java HashSet remove()方法

HashSet remove()方法用于从HashSet中删除一个特定元素。注意，它只在JDK1.2及以后的版本中使用，在JDK1和JDK1.1版本中会出现编译错误。

注意： 如果指定的元素存在于HashSet中，该方法会返回true，否则会返回boolean false。

语法

HashSet.remove(Object O)

参数： 参数O是HashSet的类型，指定要从HashSet中删除的元素。

返回值 ：布尔值 true 和 false

例子1 :

// Java code to illustrate
// HashSet.remove() method
// over String Elements
 
// Importing required classes
import java.util.*;
 
// Main class
// HashSet demo
public class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
 
        // Creating an empty HashSet
        // Declaring object of string type
        HashSet<String> set = new HashSet<String>();
 
        // Adding custom input elements into the Set
        // using add() method
        set.add("Welcome");
        set.add("To");
        set.add("Geeks");
        set.add("For");
        set.add("Geeks");
 
        // Displaying the HashSet(object elements)
        System.out.println("HashSet: " + set);
 
        // Removing elements
        // using remove() method
        set.remove("Geeks");
        set.remove("For");
        set.remove("Welcome");
 
        // Now displaying the HashSet after removal
        // of elements from it
        System.out.println(
            "HashSet after removing elements: " + set);
    }
}

输出

HashSet: [Geeks, For, Welcome, To]
HashSet after removing elements: [To]

例2 :

// Java code to illustrate remove()
// method of Hashset class
// over Integer Elements
 
// Importing required classes
import java.util.*;
 
// Main class
public class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
 
        // Creating an empty HashSet
        // Declaring object of integer type
        HashSet<Integer> set = new HashSet<Integer>();
 
        // Adding custom input elements into the Set
        // using add() method
        set.add(5);
        set.add(3);
        set.add(1);
        set.add(4);
        set.add(3);
 
        // Displaying the HashSet(object elements)
        System.out.println("HashSet: " + set);
 
        // Removing elements
        // using remove() method
        set.remove(3);
        set.remove(1);
 
        // Now displaying the HashSet after removal
        // of elements from it
        System.out.println(
            "HashSet after removing elements: " + set);
    }
}

输出

HashSet: [1, 3, 4, 5]
HashSet after removing elements: [4, 5]