PHP uasort() Function

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

Syntax

uasort(array, myfunction)

Parameters

`array`	`Required.` Specify the input array to sort.
`myfunction`	`Required.` Specify user-defined function to compare values. The comparison function must return an integer <, =, or > than 0 if the first argument is <, =, or > than the second argument.

Return Value

Returns true on success and false in failure.

Exceptions

NA.

Example:

In the example below, uasort() function is used to sort an array in ascending order, according to the value and using user-defined function.

<?php
//function to sort in ascending order
function MyFunc($x, $y) {
  if ($x == $y) 
     return 0;
  return ($x < $y)? -1: 1;
}

$Arr = array("Marry"=>25, 
             "John"=>30, 
             "Jo"=>45, 
             "Kim"=>22, 
             "Adam"=>35);
                 
uasort($Arr, "MyFunc");

print_r($Arr);
?>

The output of the above code will be:

Array
(
    [Kim] => 22
    [Marry] => 25
    [John] => 30
    [Adam] => 35
    [Jo] => 45
)

Example:

Consider one more example where the function is defined to sort the array in descending order.

<?php
//function to sort in descending order
function MyFunc($x, $y) {
  if ($x == $y) 
    return 0;
  return ($x < $y)? 1: -1;
}

$Arr = array("Marry"=>25, 
             "John"=>30, 
             "Jo"=>45, 
             "Kim"=>22, 
             "Adam"=>35);
                 
uasort($Arr, "MyFunc");

print_r($Arr);
?>

The output of the above code will be:

Array
(
    [Jo] => 45
    [Adam] => 35
    [John] => 30
    [Marry] => 25
    [Kim] => 22
)

❮ PHP Array Reference