How to convert array keys to lowercase in PHP?

Convert array keys to lowercase in PHP, we can do it simply without using a loop. We just need to use array_change_key_case(). The array_change_key_case function has two parameters, one is an array, and the other can be the constant "CASE_LOWER", so we may need to do this when doing large projects.

The following will introduce how to use array_change_key_case() to convert array values ​​to lowercase.

The PHP code example is as follows:

<?php
$myArray = [&#39;Hey&#39;=>&#39;Hey&#39;,&#39;HELLO&#39;=>&#39;Hello&#39;,&#39;hi&#39;=>&#39;Hi&#39;,&#39;Gm&#39;=>&#39;GM&#39;];
$result = array_change_key_case($myArray, CASE_LOWER);
print_r($result);

Output:

Array

Array
(
    [hey] => Hey
    [hello] => Hello
    [hi] => Hi
    [gm] => GM
)

As shown above, the keys of the associative array are converted to lowercase.

Function introduction:

array_change_key_case() changes all key names in the array to all uppercase or lowercase

array_change_key_case ( array $array [, int $case = CASE_LOWER ] ) : array

array_change_key_case() changes the array Change all key names in to all lowercase or uppercase. This function does not change the numeric index.

Parameters:

array, the array to be operated on.

case, you can use two constants here, CASE_UPPER or CASE_LOWER (default value).

Return value, return an array whose keys are all lowercase or all uppercase; if the input value (array) is not an array, then return FALSE

Note: If the input value (array) is not An array will throw an error warning (E_WARNING).

Related recommendations: "How to convert array values ​​to lowercase in PHP? 》

This article is an introduction to the method of converting array keys to lowercase in PHP. It is simple and easy to understand. I hope it will be helpful to friends in need!

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