(PHP 4, PHP 5, PHP 7, PHP 8)
strnatcmp — String comparisons using a "natural order" algorithm
This function implements a comparison algorithm that orders alphanumeric strings in the way a human being would, this is described as a "natural ordering". Note that this comparison is case sensitive.
string1The first string.
string2The second string.
Similar to other string comparison functions, this one returns -1 if
string1 is less than string2;
1 if string1 is greater than
string2, and 0 if they are equal.
| Version | Description |
|---|---|
| 8.2.0 |
This function now returns -1 or 1,
where it previously returned a negative or positive number.
|
An example of the difference between this algorithm and the regular computer string sorting algorithms (used in strcmp()) can be seen below:
<?php
$arr1 = $arr2 = array("img12.png", "img10.png", "img2.png", "img1.png");
echo "Standard string comparison\n";
usort($arr1, "strcmp");
print_r($arr1);
echo "\nNatural order string comparison\n";
usort($arr2, "strnatcmp");
print_r($arr2);
?>The above example will output:
Standard string comparison
Array
(
[0] => img1.png
[1] => img10.png
[2] => img12.png
[3] => img2.png
)
Natural order string comparison
Array
(
[0] => img1.png
[1] => img2.png
[2] => img10.png
[3] => img12.png
)