PHP Manual
Array Functions
Changes the case of all keys in an array

array_change_key_case

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

array_change_key_case — Changes the case of all keys in an array

Description

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.

Parameters

array: The array to work on
case: Either CASE_UPPER or CASE_LOWER (default)

Return Values

Returns an array with its keys lower or uppercased, or FALSE if array is not an array.

Errors/Exceptions

Throws E_WARNING if array is not an array.

Examples

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
)

Notes

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.

Php/docs/function.array-change-key-case

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