How does PHP remove an element from an array based on the key value

php The method of removing the elements in the array according to the key value ：1、 Use array_search() Function searches the array for the specified key value , And return the corresponding key name , grammar “array_search( Specified key name ,$arr,true);”;2、 Use unset() Function deletes the specified array element according to the obtained key name , grammar “unset($ Array variable name [ Key name ])”.

php The method of removing an element in the array according to the key value

Realization thought ：

Get the corresponding key name according to the key value

Use the key name to access the specified array elements , And delete the element

Implementation steps ：

1、 Use array_search() Function get key name

1. <?php
2. header('content-type:text/html;charset=utf-8');   
3. $arr=array("a"=>"red","b"=>"green","c"=>"blue");
4. var_dump($arr);
5. $key=array_search("red",$arr,true);
6. echo " Corresponding key name ：".$key;
7. ?>

2、 Use unset() Function deletes the element according to the key name

1. unset($arr[$key]);
2. var_dump($arr);

explain ：$ Array variable name [ Key name ] Statement to access the specified element

Expanding knowledge ：

array_search()  Function searches for a key value in an array , And return the corresponding key name .

1. array_search(value,array,strict)

Parameters	describe
value	It's necessary . Specify the key value to search in the array .
array	It's necessary . Specify the array to be searched .
strict	Optional . If this parameter is set to TRUE, Then the function searches the array for elements with the same data type and value . Possible value ： true false - Default If set to true, Then check the type of the given value in the array , Numbers 5 And string 5 Is different （ See Example 2）.

Return value ： If the specified key value is found in the array , The corresponding key name is returned , Otherwise return to FALSE. If the key value is found more than once in the array , The key name matched by the key value found for the first time .

unset()  Function to destroy a given variable .

notes ： The function does not return a value .

If in a function  unset()  A global variable , Only local variables are destroyed , Variables in the calling environment will remain called unset() The same value as before .