How Can I Efficiently Sort a Globbed File Array by Last Modified Datetime in PHP?

Globally Sorted File Arrays by Last Modified Datetime Stamp

Sorting files based on their last modified datetime stamp is a common task when managing and organizing file systems. The glob() function provides a quick method to retrieve files matching a specified pattern, but what if you want to further sort the resulting array by date?

Custom Sorting Approach

One approach is to iterate through the initial array and create a new array with the sorted files. While this works, it can be inefficient for larger arrays. A more efficient method exists.

Utilizing the Usort Function

PHP offers the usort() function, which sorts an array using a user-defined comparison function. This allows you to specify how the elements should be compared and ordered. In our case, we can use filemtime() to retrieve the last modified timestamp for each element and then sort the array based on these timestamps.

The following code snippet demonstrates how to sort an array of files by last modified datetime stamp using usort():

// Retrieve an array of files using glob()
$myarray = glob("*.*");

// Define a comparison function for usort()
$compare = function($a, $b) {
    return filemtime($a) - filemtime($b);
};

// Sort the array using usort()
usort($myarray, $compare);

// Now the $myarray contains files sorted by last modified timestamp

Note that this approach requires PHP version 5.3 or later, as create_function() is deprecated in PHP 7.2.0 and above. If you are using an older version of PHP, you can still achieve similar functionality using an anonymous function or a closure.

By utilizing usort() and filemtime(), you can efficiently sort an array of files by their last modified datetime stamp, providing a more organized and manageable file list.

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