How to convert php array key values ​​to lowercase

In php, you can use the array_change_key_case function to convert the array key value to lowercase. The syntax format is "array_change_key_case(array, CASE_LOWER)". When the value is CASE_LOWER, converts the array's keys to lowercase letters.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

Convert the array keys to lowercase in PHP, We can easily implement this without using loops. 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() Modifies 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 all key names in the array array 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 If the input value (array) is not an array, an error warning (E_WARNING) will be thrown.

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