This function implements a sort algorithm that orders alphanumeric strings in the way a human being would. 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 below:
The code above will generate the following output:
| Standard sorting
Array
(
    [0] => img1.png
    [1] => img10.png
    [2] => img12.png
    [3] => img2.png
)
Natural order sorting
Array
(
    [3] => img1.png
    [2] => img2.png
    [1] => img10.png
    [0] => img12.png
) | 
See also natcasesort(), strnatcmp(), and strnatcasecmp().