PHP SplDoublyLinkedList offsetUnset()函数用法示例

SplDoublyLinkedList::offsetUnset()函数是PHP中的内置函数, 用于取消给定索引处的值。

语法如下：

void SplDoublyLinkedList::offsetUnset( $index )

参数：该函数接受单个参数$ index包含要取消设置其值的索引值。

返回值：它不返回任何值。

下面的程序说明了SplDoublyLinkedList::offsetUnset()PHP中的功能：

程序1：

<?php 
  
//Declare an empty SplDoublyLinkedList
$list = new \SplDoublyLinkedList;
  
//Use SplDoublyLinkedList::add() function to 
//add elements to the SplDoublyLinkedList
$list ->add(0, 30);
$list ->add(1, 20);
$list ->add(2, 30);
$list ->add(3, "Geeks" );
$list ->add(4, 'G' );
$list -> rewind ();
  
//Use SplDoublyLinkedList::offsetUnset() function
//to unset the value at given index
$list ->offsetUnset(0);
  
$list ->offsetUnset(1);
  
$list ->offsetUnset(0);
  
$list ->offsetUnset(1);
  
var_dump( $list );
  
?>

输出如下：

object(SplDoublyLinkedList)#1 (2) {
  ["flags":"SplDoublyLinkedList":private]=>
  int(0)
  ["dllist":"SplDoublyLinkedList":private]=>
  array(1) {
    [0]=>
    string(5) "Geeks"
  }
}

程序2：

<?php 
  
//Declare an empty SplDoublyLinkedList
$list = new \SplDoublyLinkedList();
  
//Use SplDoublyLinkedList::push() function to 
//add elements to the SplDoublyLinkedList
$list ->push(1);
$list ->push(2);
$list ->push(3);
$list ->push(8);
$list ->push(5);
  
//Use SplDoublyLinkedList::offsetUnset() function
//to unset the value at given index
$list ->offsetUnset(1);
  
$list ->offsetUnset(2);
  
print_r( $list );
  
?>

输出如下：

SplDoublyLinkedList Object
(
    [flags:SplDoublyLinkedList:private] => 0
    [dllist:SplDoublyLinkedList:private] => Array
        (
            [0] => 1
            [1] => 3
            [2] => 5
        )

)

参考： https://www.php.net/manual/en/spldoublylinkedlist.offsetunset.php

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