Question

This is a question you can read everywhere on the web with various answers:

$ext = end(explode('.', $filename)); $ext = substr(strrchr($filename, '.'), 1); $ext = substr($filename, strrpos($filename, '.') + 1); $ext = preg_replace('/^.*\.([^.]+)$/D', '$1', $filename);  $exts = split("[/\\.]", $filename); $n    = count($exts)-1; $ext  = $exts[$n]; 

etc.

However, there is always "the best way".

Answer 1

People from other scripting languages always think theirs is better because they have a built-in function to do that and not PHP (I am looking at Pythonistas right now :-)).

In fact, it does exist, but few people know it. Meet pathinfo():

$ext = pathinfo($filename, PATHINFO_EXTENSION); 

This is built-in. pathinfo() can give you other information, such as canonical path, depending on the constant you pass to it.

Remember that if you want to be able to deal with non-ASCII characters, you need to set the locale first. For example:

setlocale(LC_ALL, 'en_US.UTF-8'); 

Also, note this doesn’t take into consideration the file content or MIME type, you only get the extension. But it’s what you asked for.

Lastly, note that this works only for a file path, not a URL resources path, which is covered using PARSE_URL.