How to remove a value from an array in php

Removal method: 1. Use the foreach and unset functions to delete, the syntax "foreach($arr as $k=>$v){if($v=='specified value'){unset( $array[$k]):}}"; 2. Delete using array_flip and unset functions; 3. Delete using array_search and unset functions; 4. Delete using array_splice() and unset() functions; 5. Delete using array_unique() .

The operating environment of this article: windows7 system, PHP8 version, DELL G3 computer

php deletes the number of elements with specified values ​​​​in the array Method

In some special cases, you need to delete specific values ​​in the array, and delete them all. In fact, there are many methods, we will discuss them through this article.

1. Use the foreach and unset() functions to delete specific elements in the array

<?php
header("Content-type:text/html;charset=utf-8");
$arr=[1,2,3,4,5,6,7,8];
var_dump($arr);
foreach($arr as $k=>$v){
	if($v == &#39;3&#39;){
	unset($arr[$k]);
	}
}
var_dump($arr);
?>

The unset() function deletes the specified element array value.

2. Use array_flip() function and unset() function to delete specific values ​​in the array

$arr = array_flip($arr);
unset($arr['world']);
$arr = array_flip($arr);
print_r($arr);

array_flip() is an inversion function that changes the original value of the array to The key name becomes the key value, and the key value becomes the key name, so that the above operation is easy to understand.

3. Use the array_search() and unset() functions to delete specific values ​​in the array

if(($key = array_search('day',$arr))){
unset($arr[$key]);
}

array_search() function is the same as in_array(), searching in the array A key value. If the value is found, the key of the matching element is returned. If not found, returns false.

4. The array_splice() function can play the same role as the unset() function

if(($key = array_search('day',$arr))){
array_splice($arr, $key,1);
}

array_splice() has four parameters. Please see here for usage.

5. array_unique() allows this specific value to be left in the array

Note: All the above operations only delete the first one in the array and the one you gave Elements with the same specified value, subsequent elements will not be deleted even if they are equal to the value you specified!

Before performing all the above code operations, first perform the array_unique($array) operation to merge and delete the duplicate values ​​in the array, and then perform the above deletion so that no duplicate values ​​in the array are left. .

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