scandir - sort numeric filenames

Question

Done some searching, but can't seem to find the exact answer I'm looking for.

I'd like to pull in files with numbered filenames using 'scandir($dir)', but have them sort properly. For example, file names are:

1-something.ext

2-something-else.ext

3-a-third-name.ext

.

.

.

10-another-thing.ext

11-more-names.ext

The problem I'm having is that 10-a-fourth-thing.ext will show before 2-something-else.ext. I'd like to find a better way of solving this issue than introducing leading '0' in front of all file names.

Any thoughts? Thanks.

[How to sort an array of numeric strings which also contain numbers. (natural ordering) in PHP](https://stackoverflow.com/q/28363762/2943403) and [Sorting an array of directory filenames in descending natural order](https://stackoverflow.com/q/7377015/2943403) and [Sort an array of strings starting by numbers](https://stackoverflow.com/q/63357754/2943403) and [How do I sort alphabetically with pictures in php?](https://stackoverflow.com/q/47137436/2943403) — mickmackusa, Feb 27 '23 at 02:29

Jon · Accepted Answer · 2012-03-15T20:45:17.220

16

natsort does exactly what you need.

sort with SORT_NUMERIC will also work for filenames that start with numbers, but it will break if there are also names that have no numbers in front (all non-number-prefixed names will be sorted before number-prefixed names, and their order relative to one another will be random instead of alphabetic).

edited Mar 15 '12 at 20:45

answered Mar 15 '12 at 20:39

Jon

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score 3 · Answer 2 · answered Mar 15 '12 at 20:40

3

You can use sort like this:

sort($arr, SORT_NUMERIC); // asuming $arr is your array

answered Mar 15 '12 at 20:40

anubhava

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That was my first impulse as well, but there are serious issues with it. – Jon Mar 15 '12 at 20:45
From the OP `I'd like to pull in files with numbered filenames` it appears that file names always have numbers in front. However if there are mixed ones then natsort is the way to go. – anubhava Mar 15 '12 at 20:49

score 1 · Answer 3 · answered Mar 26 '12 at 18:32

1

If you want to reassign keys (which natsort does not do), use usort() combined with strnatcmp() or strnatcasecmp():

usort($arr, 'strnatcmp'); // Or 'strnatcasecmp' for case insensitive

answered Mar 26 '12 at 18:32

RussSchick

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scandir - sort numeric filenames

3 Answers3

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