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PHP: array_change_ key_case() function

PHP: Changes the case of all keys in an array

The array_change_key_case() function is used to change all keys of a given array to lower case or upper case.

Version:

(PHP 4 and above)

Syntax:

array_change_key_case (input_array, input_case)

Parameters:

Name Description Required /
Optional 		Type
input_array Specifies the array to work with. Required Array
input_case Either CASE_UPPER or CASE_LOWER.
Default value : CASE_LOWER		 Optional Integer

Return value:

An array with its keys lowercased or uppercased. Returns FALSE if the input is not an array.

Value Type: Array

Example:

<?php
$input_array = array("India"=> 100,"China" => 125);
print_r(array_change_key_case($input_array,CASE_UPPER));
?>

Output :

Array  ( [INDIA] => 100 [CHINA] => 125  )

Pictorial Presentation:

php function reference: array_change_ key_case() function

View the example in browser

Practice here online :

See also

PHP Function Reference

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Next: array_chunk



PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC