(PHP 4, PHP 5, PHP 7, PHP 8)
natsort — Sort an array using a "natural order" algorithm
This function implements a sort algorithm that orders alphanumeric strings in the way a human being would while maintaining key/value associations. This is described as a "natural ordering". An example of the difference between this algorithm and the regular computer string sorting algorithms (used in sort()) can be seen in the example below.
Note:
If two members compare as equal, they retain their original order. Prior to PHP 8.0.0, their relative order in the sorted array was undefined.
Note:
Resets array's internal pointer to the first element.
array
The input array.
Always returns true
.
Example #1 natsort() examples demonstrating basic usage
<?php$array1 = $array2 = array("img12.png", "img10.png", "img2.png", "img1.png");asort($array1);echo "Standard sorting\n";print_r($array1);natsort($array2);echo "\nNatural order sorting\n";print_r($array2);?>
The above example will output:
Standard sorting Array ( [3] => img1.png [1] => img10.png [0] => img12.png [2] => img2.png ) Natural order sorting Array ( [3] => img1.png [2] => img2.png [1] => img10.png [0] => img12.png )
For more information see: Martin Pool's » Natural Order String Comparison page.
Example #2 natsort() examples demonstrating potential gotchas
<?phpecho "Negative numbers\n";$negative = array('-5','3','-2','0','-1000','9','1');print_r($negative);natsort($negative);print_r($negative);echo "Zero padding\n";$zeros = array('09', '8', '10', '009', '011', '0'); print_r($zeros);natsort($zeros);print_r($zeros);?>
The above example will output:
Negative numbers Array ( [0] => -5 [1] => 3 [2] => -2 [3] => 0 [4] => -1000 [5] => 9 [6] => 1 ) Array ( [2] => -2 [0] => -5 [4] => -1000 [3] => 0 [6] => 1 [1] => 3 [5] => 9 ) Zero padding Array ( [0] => 09 [1] => 8 [2] => 10 [3] => 009 [4] => 011 [5] => 0 ) Array ( [5] => 0 [1] => 8 [3] => 009 [0] => 09 [2] => 10 [4] => 011 )