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PHP array_change_key_case() Function

Definition and Usage

The array_change_key_case() function returns an array with all array KEYS in lower case or upper case.

array_change_key_case(array,case)

Parameter	Description
array	Required. Specifies the array to use
case	Optional. Possible values: CASE_LOWER - Deafult value. Returns the array key values in lower case. CASE_UPPER - Returns the array key values in upper case.

Note: If two or more array keys will be the same after running this function, the last array will override the others. (See example 2)

<?php
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse");
print_r(array_change_key_case($a,CASE_UPPER));
?>

The output of the code above will be:

Array ( [A] => Cat [B] => Dog [C] => Horse )

<?php
$a=array("a"=>"Cat","b"=>"Dog","c"=>"Horse","B"=>"Bird");
print_r(array_change_key_case($a,CASE_UPPER));
?>

The output of the code above will be:

Array ( [A] => Cat [B] => Bird [C] => Horse )