Java ArrayDeque pollLast()方法

java.util.ArrayDeque.pollLast() 此方法检索并删除此双端队列的最后一个元素，如果此双端队列为空，则返回null。

1 语法

public E pollLast()

2 参数

无

3 返回值

此方法返回此双端队列的尾部；如果此双端队列为空，则返回null。

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 *  java.util.ArrayDeque.pollLast()方法的例子
 */
import java.util.ArrayDeque;
import java.util.Deque;

public class Demo {
    public static void main(String[] args) {

        // create an empty array deque with an initial capacity
        Deque<Integer> deque = new ArrayDeque<Integer>(8);

        // use add() method to add elements in the deque
        deque.add(25);
        deque.add(30);
        deque.add(20);
        deque.add(18);

        // printing all the elements available in deque
        for (Integer number : deque) {
            System.out.println("Number = " + number);
        }
        int retval = deque.pollLast();
        System.out.println("Element removed is " + retval);

        // printing all the elements available in deque after using pollLast()
        for (Integer number : deque) {
            System.out.println("Number = " + number);
        }
    }
}

输出结果为：

Number = 25
Number = 30
Number = 20
Number = 18
Element removed is 18
Number = 25
Number = 30
Number = 20