poll java_Java ArrayDeque poll（）方法与示例

冷不防 2023-03-05 13:29 13阅读 0赞

poll java

## ArrayDeque类poll()方法 **(**ArrayDeque Class poll() method**)** ##

*  **poll() Method** is available in java.lang package.
    
    **poll()方法**在java.lang包中可用。
 *  **poll() Method** is used to return the head element of the queue denoted by this deque but with removing the head element from this deque.
    
    **poll()方法**用于返回此双端队列表示的队列的head元素，但要从此双端队列中删除head元素。
 *  **poll() Method** is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
    
    **poll()方法**是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。
 *  **poll() Method** does not throw an exception at the time retrieving the head element of this deque.
    
    **poll()方法**在检索此双端队列的head元素时不会引发异常。

**Syntax:**

**句法：**

public T poll();

**Parameter(s):**

**参数：**

*  It does not accept any parameter.
    
    它不接受任何参数。

**Return value:**

**返回值：**

The return type of the method is T, it returns the head element denoted by this deque otherwise it returns null, when this deque is "blank".

方法的返回类型为T ，它返回此双端队列表示的head元素，否则当此双端队列为“空白”时返回null。

**Example:**

**例：**

// Java program to demonstrate the example 
    // of T poll() method of ArrayDeque 
    
    import java.util.*;
    
    public class PollOfArrayDeque {
        
        public static void main(String[] args) {
        
            // Creating an ArrayDeque with initial capacity of
            // storing elements
            Deque < String > d_queue = new ArrayDeque < String > (10);
    
            // By using add() method to add elements
            // in ArrayDeque
            d_queue.add("C");
            d_queue.add("C++");
            d_queue.add("Java");
            d_queue.add("Php");
            d_queue.add("DotNet");
    
            // Display Deque Elements
            System.out.println("d_queue before poll(): ");
            System.out.println("ArrayDeque Elements = " + d_queue);
    
            System.out.println();
    
            // By using poll() method to remove and return the
            // element at the first position in ArrayDeque
            String ele = d_queue.poll();
    
            // Display Returned Elements
            System.out.println("d_queue.poll() : " + ele);
    
            System.out.println();
    
            // Display Deque Elements
            System.out.println("d_queue after poll(): ");
            System.out.println("ArrayDeque Elements = " + d_queue);
        }
    }

**Output**

**输出量**

d_queue before poll(): 
    ArrayDeque Elements = [C, C++, Java, Php, DotNet]
    
    d_queue.poll() : C
    
    d_queue after poll(): 
    ArrayDeque Elements = [C++, Java, Php, DotNet]

> 翻译自: [https://www.includehelp.com/java/arraydeque-poll-method-with-example.aspx][https_www.includehelp.com_java_arraydeque-poll-method-with-example.aspx]

poll java

[https_www.includehelp.com_java_arraydeque-poll-method-with-example.aspx]: https://www.includehelp.com/java/arraydeque-poll-method-with-example.aspx