How to Sort Date Arrays Ascendingly in PHP?

Sorting Date Arrays in PHP

PHP provides several ways to sort arrays, including date arrays. This article will demonstrate how to sort a PHP date array according to date values.

Problem:

Consider the following PHP date array:

<code class="php">[0] => 11-01-2012
[1] => 01-01-2014
[2] => 01-01-2015
[3] => 09-02-2013
[4] => 01-01-2013</code>

The goal is to sort the array in ascending order of dates, resulting in the following sorted array:

<code class="php">[0] => 11-01-2012
[1] => 01-01-2013
[2] => 09-02-2013
[3] => 01-01-2014
[4] => 01-01-2015</code>

Solution:

If the dates in the array are stored in the format "Y-m-d" or "Y-m-d H:i:s," you can sort the array directly using sort():

<code class="php">$arr = ["2019-11-11", "2019-10-10","2019-11-11", "2019-09-08","2019-05-11"];
sort($arr);</code>

However, if the date format is localized or not in a sortable format, you need to use a custom sorting function such as usort(). This function compares two elements of the array, converts them into a sortable format, and returns a value that indicates the sorting order:

<code class="php">$arr = ['11/01/2012', '03/16/2022', '12/26/2021', '01/01/2014', '09/02/2013'];
usort($arr, function ($a, $b) {
    return strtotime($a) - strtotime($b);
});</code>

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