java.util.LinkedHashSet類的removeAll()方法用於從該集合中刪除指定集合中包含的所有其元素。
用法:
public boolean removeAll(Collection c)
參數:此方法將集合c作為包含要從此集合中刪除的元素的參數。
返回值:如果此集合因調用而更改,則此方法返回true。
異常:如果此集合包含null元素並且指定的集合不允許null元素(可選),或者指定的collection為null,則此方法引發NullPointerException。
以下示例說明了removeAll()方法。
示例1:
// Java program to demonstrate
// removeAll() method for Integer value
import java.util.*;
public class GFG1 {
public static void main(String[] argv) throws Exception
{
try {
// Creating object of LinkedHashSet<Integer>
LinkedHashSet<Integer>
set1 = new LinkedHashSet<Integer>();
// Populating set1
set1.add(1);
set1.add(2);
set1.add(3);
set1.add(4);
set1.add(5);
// print set1
System.out.println("LinkedHashSet before "
+ "removeAll() operation : "
+ set1);
// Creating another object of LinkedHashSet<Integer>
LinkedHashSet<Integer>
set2 = new LinkedHashSet<Integer>();
set2.add(1);
set2.add(2);
set2.add(3);
// print set2
System.out.println("Collection Elements"
+ " to be removed : "
+ set2);
// Removing elements from set
// specified in set2
// using removeAll() method
set1.removeAll(set2);
// print set1
System.out.println("LinkedHashSet after "
+ "removeAll() operation : "
+ set1);
}
catch (NullPointerException e) {
System.out.println("Exception thrown : " + e);
}
}
}
輸出:
LinkedHashSet before removeAll() operation : [1, 2, 3, 4, 5] Collection Elements to be removed : [1, 2, 3] LinkedHashSet after removeAll() operation : [4, 5]
示例2:對於NullPointerException
// Java program to demonstrate
// removeAll() method for Integer value
import java.util.*;
public class GFG1 {
public static void main(String[] argv) throws Exception
{
try {
// Creating object of LinkedHashSet<Integer>
LinkedHashSet<Integer>
set1 = new LinkedHashSet<Integer>();
// Populating set1
set1.add(1);
set1.add(2);
set1.add(3);
set1.add(4);
set1.add(5);
// print set1
System.out.println("LinkedHashSet before "
+ "removeAll() operation : "
+ set1);
// Creating another object of LinkedHashSet<Integer>
LinkedHashSet<Integer>
set2 = null;
// print set2
System.out.println("Collection Elements"
+ " to be removed : "
+ set2);
System.out.println("\nTrying to pass "
+ "null as a specified element\n");
// Removing elements from set
// specified in set2
// using removeAll() method
set1.removeAll(set2);
// print set1
System.out.println("LinkedHashSet after "
+ "removeAll() operation : "
+ set1);
}
catch (NullPointerException e) {
System.out.println("Exception thrown : " + e);
}
}
}
輸出:
LinkedHashSet before removeAll() operation : [1, 2, 3, 4, 5] Collection Elements to be removed : null Trying to pass null as a specified element Exception thrown : java.lang.NullPointerException
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注:本文由純淨天空篩選整理自Code_r大神的英文原創作品 LinkedHashSet removeAll() 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。