Java ArrayDeque removeAll()用法及代码示例

ArrayDeque的removeAll()方法用于删除ArrayDeque和作为参数传递的集合中共同的所有元素。此方法首先收集Collection的所有元素，然后开始从ArrayDeque中删除与Collection元素相同的元素。执行此方法后，此ArrayDequeu将不包含与集合相同的元素。如果此ArrayDeque由于调用此方法而发生更改，则此方法为True。

用法:

public boolean removeAll(Collection<? extends E> col)

参数：此方法采用参数c，该参数表示我们要从此双端队列删除的元素的Collection。

返回值：如果此双端队列由于调用此方法而发生更改，则此方法返回True。

异常：如果指定的集合或其任何元素为null，则此方法将引发NullPointerException。

以下示例程序旨在说明ArrayDeque的removeAll()方法：
示例1:程序演示ArrayDeque上的removeAll()方法，该方法将从包含Numbers的集合中删除与其元素相同的元素。

// Java Program Demonstrate removeAll() 
// method of ArrayDeque 
  
import java.util.*; 
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // create an ArrayDeque which going to 
        // contains a list of Numbers 
        ArrayDeque<Integer> Numbers = new ArrayDeque<Integer>(); 
  
        // Add Number to list 
        Numbers.add(23); 
        Numbers.add(32); 
        Numbers.add(45); 
        Numbers.add(63); 
  
        // print ArrayDeque before calling removeAll() 
        System.out.println("Before calling removeAll()"); 
        print(Numbers); 
  
        // create a collection of Number to 
        // remove elements from ArrayDeque using removeAll() 
        ArrayList<Integer> col = new ArrayList<Integer>(); 
  
        // add Numbers to collection 
        col.add(45); 
        col.add(44); 
        col.add(63); 
  
        // remove Numbers same as elements of collection 
        // from ArrayDeque using removeAll() 
        Numbers.removeAll(col); 
  
        // print ArrayDeque after calling removeAll() 
        System.out.println("After calling removeAll()"); 
        print(Numbers); 
    } 
  
    // printing all elements of ArrayDeque 
    public static void print(ArrayDeque<Integer> arDe) 
    { 
  
        arDe.forEach((n) -> System.out.print(n + " ")); 
  
        System.out.println(); 
    } 
}

输出：

Before calling removeAll()
23 32 45 63 
After calling removeAll()
23 32

示例2:该程序演示ArrayDeque上的removeAll()方法，该方法将从学生名集合中删除与其元素相同的元素。

// Java Program Demonstrate removeAll() 
// method of ArrayDeque 
  
import java.util.*; 
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // create an ArrayDeque which going to 
        // contains a list of Student names which is actually 
        // string values 
        ArrayDeque<String> students = new ArrayDeque<String>(); 
  
        // Add Strings to list 
        // each string represents student name 
        students.add("Ram"); 
        students.add("Mohan"); 
        students.add("Sohan"); 
        students.add("Rabi"); 
  
        // print ArrayDeque before calling removeAll() 
        System.out.println("Before calling removeAll()"); 
        print(students); 
  
        // create a collection of Number to 
        // remove elements from ArrayDeque using removeAll() 
        LinkedList<String> col = new LinkedList<String>(); 
  
        // add Names in collection 
        col.add("Rabi"); 
        col.add("Sohan"); 
  
        // remove the elements same as collection 
        // from ArrayDeque using removeAll() 
        students.removeAll(col); 
  
        // print ArrayDeque 
        System.out.println("After calling removeAll()"); 
        print(students); 
    } 
  
    // printing all elements of ArrayDeque 
    public static void print(ArrayDeque<String> arDe) 
    { 
  
        System.out.println("List of Students Name:"); 
  
        arDe.forEach((n) -> System.out.print(" | " + n + " | ")); 
  
        System.out.println("\n"); 
    } 
}

输出：

Before calling removeAll()
List of Students Name:
 | Ram |  | Mohan |  | Sohan |  | Rabi | 

After calling removeAll()
List of Students Name:
 | Ram |  | Mohan |

示例3:该程序演示removeAll()方法引发的异常。

// Java Program Demonstrate Exception thrown by removeAll() 
// method of ArrayDeque 
  
import java.util.*; 
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // create an ArrayDeque which going to 
        // contains a list of Numbers 
        ArrayDeque<Integer> Numbers = new ArrayDeque<Integer>(); 
  
        // Add Number to list 
        Numbers.add(223); 
        Numbers.add(132); 
        Numbers.add(345); 
        Numbers.add(563); 
  
        // create a collection of Number which is null 
        ArrayList<Integer> col = null; 
  
        try { 
            // call removeAll() method 
            Numbers.removeAll(col); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

输出：

java.lang.NullPointerException

参考： https://docs.oracle.com/javase/10/docs/api/java/util/ArrayDeque.html#removeAll(java.util.Collection)

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注：本文由纯净天空筛选整理自AmanSingh2210大神的英文原创作品 ArrayDeque removeAll() method in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。