How to use usort in PHP
In this article, I will explain how the usort() function can be used in PHP.
usort() function in PHP
- The usort() function is used to sort an array by it's value using a user-made comparison function.
- The usort() function does not assigns new keys for the elements.
- The usort() function is useful for sorting with custom algorithms.
- The usort() function maintains the existing key index.
- The usort() function returns TRUE on success, or FALSE on failure.
Syntax
Parameter
- array array is required parameter. the determine array to be sort.
-
function function is required parameter. the function must return -1, 0, or 1 for this method to work correctly. It should be written to accept two parameters to compare.
- If a = b, return 0
- If a > b, return 1
- If a < b, return -1
Example
The following example show to how the usort() function can be used in PHP.
<html>
<body>
<h3 style="color: green;">usort() function example in PHP</h3>
<?php
function my_sortdemo($a, $b)
{
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}
$people_list = array("Nitin".'<br/>', "Arvind".'<br/>',"Rajesh".'<br/>',
"Peter".'<br/>',"Manish".'<br/>', "Sachin".'<br/>');
usort($people_list, "my_sortdemo");
print_r ($people_list);
?>
</body>
</html>
|
Output
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