How to change array keys from uppercase to lowercase?

The array_change_key_case() function changes all keys in an array to lowercase or uppercase.

Syntax:

This function takes array as a first parameter, It will return FALSE if given input is not an array.
Second parameter is optional,you can pass either CASE_LOWER or CASE_UPPER and default value is “CASE_LOWER”. This function is supported from PHP 4.2 and above.

Example :

Example :

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