Pathinfo does a number of things, depending on what we ask of it, but put simply it returns (path) information about a filepath. Full details can be found on the handy dandy pathinfo page in the PHP manual. Explore the PHP manual page when you get time, but for the purpose of this blog post I’ll hone in to one specific use of the function: getting the file extension. In order to do that, we simply call the function passing along the full filename and a ‘flag’ (a constant which dictates the behaviour of the function) asking for the extension only.

$filename = 'mypic.gif';
$ext = pathinfo($filename, PATHINFO_EXTENSION);

That’s all there is to it! In my opinion, this approach ‘reads’ much more easily than the mess of nested function calls and playing around with string positions, regular expressions, etc.. It is concise and to the point: call pathinfo and only give me back the extension. Simple.

Now for the icing on the cake. When pitched against the other methods detailed above, this call to pathinfo beats all of the others into submission. At least in my testing, it is the fastest method of all (though in random hiccups strrchr does win in around 1% of tests) being on average 1/10^th faster than even the strrchr approach.