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# natsort

(PHP 4, PHP 5)

natsortSort an array using a "natural order" algorithm

### Description

bool 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.

array

The input array.

### Return Values

Returns TRUE on success or FALSE on failure.

### Changelog

Version Description
5.2.10 Zero padded numeric strings (e.g., '00005') now essentially ignore the 0 padding.

### Examples

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); echo "Other characters interfering\n";\$images_oops = array('image_1.jpg','image_12.jpg', 'image_21.jpg', 'image_4.jpg');print_r(\$images_oops);natsort(\$images_oops);print_r(\$images_oops); echo "Sort by keys\n";\$smoothie = array('orange' => 1, 'apple' => 1, 'yogurt' => 4, 'banana' => 4);print_r(\$smoothie);uksort( \$smoothie, 'strnatcmp');print_r(\$smoothie);?>```

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
)

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
)

Other characters interfering
Array
(
[0] => image_1.jpg
[1] => image_12.jpg
[2] => image_21.jpg
[3] => image_4.jpg
)
Array
(
[0] => image_1.jpg
[3] => image_4.jpg
[1] => image_12.jpg
[2] => image_21.jpg
)

Sort by keys
Array
(
[orange] => 1
[apple]  => 1
[yogurt] => 4
[banana] => 4
)
Array
(
[apple]  => 1
[banana] => 4
[orange] => 1
[yogurt] => 4
)
```