Java ArrayDeque pollLast()用法及代碼示例

Java中的java.util.ArrayDeque.pollLast()方法用於檢索或獲取並刪除Deque的最後一個元素。 peekLast()方法僅在末尾檢索元素，但pollLast()也在檢索時刪除了該元素。如果雙端隊列為空，則返回NULL。

用法:

Array_Deque.pollLast()

參數：該方法不帶任何參數。

返回值：該方法刪除Deque的最後一個元素，並返回該元素。如果雙端隊列為空，則返回NULL。

下麵的程序演示了Java.util.ArrayDeque.pollLast()方法：
示例1:

// Java code to illustrate pollLast() 
import java.util.*; 
  
public class ArrayDequeDemo { 
    public static void main(String args[]) 
    { 
        // Creating an empty ArrayDeque 
        Deque<String> de_que = new ArrayDeque<String>(); 
  
        // Use add() method to add elements into the Deque 
        de_que.add("Welcome"); 
        de_que.add("To"); 
        de_que.add("Geeks"); 
        de_que.add("4"); 
        de_que.add("Geeks"); 
  
        // Displaying the ArrayDeque 
        System.out.println("ArrayDeque: " + de_que); 
  
        // Displaying the last element 
        System.out.println("The last element is: " + 
                                    de_que.pollLast()); 
  
        // Displaying the final ArrayDeque 
        System.out.println("ArrayDeque after operation: "
                                                + de_que); 
    } 
}

輸出：

ArrayDeque: [Welcome, To, Geeks, 4, Geeks]
The last element is: Geeks
ArrayDeque after operation: [Welcome, To, Geeks, 4]

示例2:

// Java code to illustrate pollLast() 
import java.util.*; 
  
public class ArrayDequeDemo { 
    public static void main(String args[]) 
    { 
        // Creating an empty ArrayDeque 
        Deque<Integer> de_que = new ArrayDeque<Integer>(); 
  
        // Use add() method to add elements into the Deque 
        de_que.add(10); 
        de_que.add(15); 
        de_que.add(30); 
        de_que.add(20); 
        de_que.add(5); 
  
        // Displaying the ArrayDeque 
        System.out.println("ArrayDeque: " + de_que); 
  
        // Displaying the last element 
        System.out.println("The element at head is: " + 
                                       de_que.pollLast()); 
  
        // Displaying the final ArrayDeque 
        System.out.println("ArrayDeque after operation: "
                                                + de_que); 
    } 
}

輸出：

ArrayDeque: [10, 15, 30, 20, 5]
The element at head is: 5
ArrayDeque after operation: [10, 15, 30, 20]

示例3:對於空的雙端隊列：

// Java code to illustrate pollLast() 
import java.util.*; 
  
public class ArrayDequeDemo { 
    public static void main(String args[]) 
    { 
        // Creating an empty ArrayDeque 
        Deque<Integer> de_que = new ArrayDeque<Integer>(); 
  
        // Displaying the ArrayDeque 
        System.out.println("ArrayDeque: " + de_que); 
  
        // Displaying the last element 
        System.out.println("The element at head is: " + 
                                       de_que.pollLast()); 
    } 
}

輸出：

ArrayDeque: []
The element at head is: null

相關用法

注：本文由純淨天空篩選整理自Chinmoy Lenka大神的英文原創作品 ArrayDeque pollLast() 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。