How Can I Sort Files Retrieved with PHP\'s glob() Function by Their Last Modified Date?

Sorting Files by Last Modified Date using glob()

When working with file systems, it's often desirable to organize files based on their attributes, such as their modification time. In PHP, the glob() function can be used to retrieve an array of files, but by default, it does not retain the order of the files.

Challenge: Sorting by Modification Date

Suppose you have an array of files obtained using glob(), and you want to sort this array based on the last modified datetime stamp of each file. Looping through the array and manually sorting it into a separate array is a viable option, but it's not the most efficient or convenient approach.

Solution: Using create_function()

Prior to PHP 7.2, the create_function() function provided a way to define anonymous functions. It could be used in conjunction with usort() to compare the modification time of files and sort the array accordingly:

usort($myarray, create_function('$a,$b', 'return filemtime($a) - filemtime($b);'));

In this code, create_function() defines an anonymous function that subtracts the modification time of the first file ($a) from that of the second file ($b). The result of this subtraction indicates their chronological order. usort() then uses this function to sort the $myarray in ascending order based on modification time.

Deprecation of create_function()

Unfortunately, create_function() has been deprecated in PHP 7.2 and removed in PHP 8.0. This means that the above code will no longer work in modern versions of PHP.

Alternative Solutions

Alternative solutions for sorting files by last modified date using glob() include:

• Using a comparison function with usort(): Define a custom comparison function that leverages the filemtime() function and passes it to usort().
• Using the sort() function with the SORT_NATURAL flag: If your file names are structured in a way that allows for natural sorting, you can use the sort() function with the SORT_NATURAL flag.

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