PHP reference

strnatcmp

Compares strings in "natural" order — numbers inside strings as numbers.

Syntax

strnatcmp(string $string1, string $string2): int

Parameters

Parameter	Type	Description
$string1	string	The first string.
$string2	string	The second string.

Return value

intA negative number, `0` or a positive number.

Examples

Regular and natural comparison:

<?php
 
$files = ['img12.png', 'img10.png', 'img2.png'];
 
sort($files);
echo implode(', ', $files), "\n";
 
usort($files, 'strnatcmp');
echo implode(', ', $files);

Output:

img10.png, img12.png, img2.png
img2.png, img10.png, img12.png

Notes

The case-insensitive variant is strnatcasecmp().

In the tutorial

Sorting arrays — Sorting in PHP — sort, rsort, asort, ksort, a custom rule with usort and the spaceship operator.

Thanks for reading!