(PHP 4 >= 4.2.0, PHP 5, PHP 7)
array_change_key_case — Changes the case of all keys in an array
array_change_key_case ( array $array [, int $case = CASE_LOWER ] ) : array
Returns an array with all keys from array lowercased or uppercased. Numbered indices are left as is.
array
The array to work on
case
Either CASE_UPPER or CASE_LOWER (default)
Returns an array with its keys lower or uppercased, or false if array is not an array.
Throws E_WARNING if array is not an array.
Example #1 array_change_key_case() example
<?php
$input_array = array("FirSt" => 1, "SecOnd" => 4);
print_r(array_change_key_case($input_array, CASE_UPPER));
?> The above example will output:
Array
(
[FIRST] => 1
[SECOND] => 4
)
Note:
If an array has indices that will be the same once run through this function (e.g. "
keY" and "kEY"), the value that is later in the array will override other indices.
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https://www.php.net/manual/en/function.array-change-key-case.php