PHP Array natcasesort() Function

Last Updated : 17 Mar 2025

The natcasesort( ) function is used to sort an array using a case insensitive "natural array" algorithm. The function implements a sort algorithm but maintains original keys and values. This function was introduced in PHP 4.0.

Syntax

Parameter

Parameter	Description	Is compulsory
array	The input array.	compulsory

Returns

The natcasesort( ) function returns true on success or false on failure.

Example 1

Output:

Standard sorting
Array
(
    [0] => Rahul
    [1] => Sachin
    [2] =>sehwag
    [3] =>virat
)
Natural order case insensitve: Array
(
    [2] => Rahul
    [0] => Sachin
    [1] =>sehwag
    [3] =>virat
)

Example 2

Output:

Standard sorting
Array
(
    [0] => Code1.php
    [1] => Code22.txt
    [2] => code12.php
    [3] => code2.php
    [4] => code3.php
)
Natural order case insensitve: Array
(
    [4] => Code1.php
    [2] => code2.php
    [3] => code3.php
    [0] => code12.php
    [1] => Code22.txt
)

Example 3

Output:

Standard sorting
Array
(
    [0] => IMG0.png
    [1] => IMG3.png
    [2] => img1.png
    [3] => img10.png
    [4] => img12.png
    [5] => img2.png
)
Natural order case insensitve: Array
(
    [0] => IMG0.png
    [4] => img1.png
    [3] => img2.png
    [5] => IMG3.png
    [2] => img10.png
    [1] => img12.png
)

Example 4

Output:

Standard sorting
Array
(
    [0] => Java
    [1] => Python
    [2] => Swift
    [3] =>php
)
Natural order case insensitve: Array
(
    [0] => Java
    [1] =>php
    [3] => Python
    [2] => Swift
)

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