Java ArrayDeque removeAll()用法及代碼示例

ArrayDeque的removeAll()方法用於刪除ArrayDeque和作為參數傳遞的集合中共同的所有元素。此方法首先收集Collection的所有元素，然後開始從ArrayDeque中刪除與Collection元素相同的元素。執行此方法後，此ArrayDequeu將不包含與集合相同的元素。如果此ArrayDeque由於調用此方法而發生更改，則此方法為True。

用法:

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

參數：此方法采用參數c，該參數表示我們要從此雙端隊列刪除的元素的Collection。

返回值：如果此雙端隊列由於調用此方法而發生更改，則此方法返回True。

異常：如果指定的集合或其任何元素為null，則此方法將引發NullPointerException。

以下示例程序旨在說明ArrayDeque的removeAll()方法：
示例1:程序演示ArrayDeque上的removeAll()方法，該方法將從包含Numbers的集合中刪除與其元素相同的元素。

// 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(); 
    } 
}

輸出：

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

示例2:該程序演示ArrayDeque上的removeAll()方法，該方法將從學生名集合中刪除與其元素相同的元素。

// 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"); 
    } 
}

輸出：

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

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

示例3:該程序演示removeAll()方法引發的異常。

// 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); 
        } 
    } 
}

輸出：

java.lang.NullPointerException

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

相關用法

注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 ArrayDeque removeAll() method in Java。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。