PHP - Array usort() Function

The PHP Array usort() function is used to sort an indexed array using user-defined comparison function. The function must return an integer to work correctly and it should take only two parameters to compare.

Syntax

usort(array, myfunction)

Parameters

`array`	`Required.` Specify the indexed array to sort
`myfunction`	`Required.` Specify user-defined function to compare keys. The function must return an integer to work correctly and it should take only two parameters to compare.

Return Value

Returns TRUE on success and False in failure.

Exceptions

NA.

Example:

In the example below, usort() function is used to sort an indexed array called MyArray using user-defined function MyFunction.

<?php
function MyFunction($x, $y) {
  if ($x == $y) 
    return 0;
  return ($x < $y)? -1: 1;
}

$MyArray = array("Marry", "John", "Jo", "Kim", "Adam");
usort($MyArray, "MyFunction");

print_r($MyArray);
?>

The output of the above code will be:

Array
(
    [0] => Adam
    [1] => Jo
    [2] => John
    [3] => Kim
    [4] => Marry
)

❮ PHP Array functions