natsort

Sort an array using a "natural order" algorithm

&reftitle.description; `true` `natsort` `array` `array`

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.

¬e.sort-unstable; ¬e.reset-index;
&reftitle.parameters;

`array`

- The input array.

&reftitle.returnvalues;

&return.true.always;

&reftitle.changelog;

&Version; | &Description;
&return.type.true;

&reftitle.examples;

### `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);
    ?>

&example.outputs;

    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.

### `natsort` examples demonstrating potential gotchas

    <?php
    echo "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);
    ?>

&example.outputs;

    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
    )

&reftitle.seealso;

- `natcasesort`
- &seealso.array.sorting;
- `strnatcmp`
- `strnatcasecmp`