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PHP usort() Function
PHP usort() Function
PHP usort() function is used to sort any given input array using the user-defined comparison function. It assigns a new integral key starting from zero to the number of elements present in the array and the old keys are lost. It returns a boolean type value TRUE in case of success and FALSE on failure.
Syntax:
usort($array, function);
Parameter Values
| Parameter | Description |
|---|---|
| array | This is a required parameter. It defines the array to sort. |
| function | This is an optional parameter. It defines the callable comparison function. |
Here is an example of usort() function in PHP:
<html>
<body>
<?php
function compare($a,$b)
{
if ($a==$b) return 0;
return ($a<$b)?-1:1;
}
$arr=array(62,4,2,41,8,15,6,25);
usort($arr,"compare");
$length=count($arr);
for($x=0;$x<$length;$x++)
{
echo $arr[$x];
echo "<br>";
}
?>
</body>
</html>
Output:
2
4
6
8
15
25
41
62
2
4
6
8
15
25
41
62
Example 2:
<html>
<body>
<pre>
<?php
function compare($a,$b)
{
if ($a==$b) return 0;
return ($a<$b)?-1:1;
}
$arr=array(62,4,2,41,8,15,6,25);
usort($arr,"compare");
print_r($arr);
?>
</pre>
</body>
</html>
Output:
Array
(
[0] => 2
[1] => 4
[2] => 6
[3] => 8
[4] => 15
[5] => 25
[6] => 41
[7] => 62
)
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