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    PHP array_change_key_case() Function

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    Definition and Usage

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

    Syntax

    array_change_key_case(array, case)

    Parameter Values

    Parameter Description
    array Required. Specifies the array to use
    case Optional. Possible values:
    • CASE_LOWER - Default value. Changes the keys to lowercase
    • CASE_UPPER - Changes the keys to uppercase

    Technical Details

    Return Value: Returns an array with its keys in lowercase or uppercase, or FALSE if array is not an array
    PHP Version: 4.2+

    Examples

    Example 1: Change all keys in an array to lowercase

    Change all keys in an array to lowercase:

    <?php
$age=array("Peter"=>"35","Ben"=>"37","Joe"=>"43");
print_r(array_change_key_case($age,CASE_LOWER));
?>
    Example 2: Special rules for changing key case

    If two or more keys will be equal after running array_change_key_case() (e.g. "b" and "B"), the latest array will override the other:

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

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    PHP Referrence: The PHP reference contains different categories of all PHP functions, keywords and constants, along with examples.

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  • array() Function
  • array_change_key_case() Function
  • array_chunk() Function
  • array_combine() Function
  • array_count_values() Function
  • arsort() Function
  • asort() Function
  • count() Function
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    PHP Quiz

    Example files created in this segment:
    Indexed Arrays Associative Arrays Loop Through an Indexed Array Loop Through an Associative Array Two-dimensional Array Change all keys in an array to lowercase Special rules for changing key case PHP Array - array_chunk() Function part 1 PHP Array - array_chunk() Function part 2 PHP array_combine() Function PHP array_count_values() Function PHP arsort() Function PHP asort() Function PHP count() Function part 1 count() Function part 2