Homework on PHP array functions

In PHP, there are plenty of PHP function which are very handy to smoothly build a web application. Currently, I find of 82 array functions and 13 array sorting functions. May be count of functions will be increase on time.

Notes: I will write about all array functions as time being.

  1. array_change_key_case
    This function is self explanatory. It will change keys of an array, if keys are string.
    For one dimensional array, array_change_key_case() simply change the keys in uppercase or lowercase (default case). But, for multidimensional array it will be tricky. Following are both types array example
$simple_array = [
    'AppLe' => 'Mrinal',
    'OraNge' => 'Shuchy',
    'PeNut' => 'Sukla',
];
$convert_key_simple_array = array_change_key_case( $simple_array, CASE_UPPER);
print_r($convert_key_simple_array);

To change keys of multidimensional array use this function