PHP uksort
Summary: in this tutorial, you’ll learn how to use the PHP uksort() function to sort an array by keys using a user-defined comparison function.
Introduction to the PHP uksort() function
The uksort() function allows you to sort an array by key using a user-defined comparison function. Typically, you use the uksort() function to sort the keys of an associative array.
The following shows how to use the uksort() function’s syntax:
uksort(array &$array, callable $callback): boolCode language: PHP (php)
The uksort() function has two parameters:
$arrayis the input array.$callbackis the comparison function that determines the order of keys.
Here’s the syntax of the callback function:
callback(mixed $x, mixed $y): intCode language: PHP (php)
The callback function returns an integer less than, equal to, or greater than zero if $x is less than, equal to, or greater than $y.
The uksort() function returns a boolean value, true on success or false on failure.
The PHP uksort() function example
The following example shows how to use the uksort() function to sort the keys of the $name array case-insensitively:
$names = [
'c' => 'Charlie',
'A' => 'Alex',
'b' => 'Bob'
];
uksort(
$names,
fn ($x, $y) => strtolower($x) <=> strtolower($y)
);
print_r($names);
Code language: PHP (php)
Output:
Array
(
[A] => Alex
[b] => Bob
=> Charlie
)Code language: PHP (php)
Summary
- Use the
uksort()function to sort an array by key using a user-defined comparison function.