PHP Functions to Get and Remove the File Extension from a String

Published on March 11, 2009

I use these regular expressions all the time, but it’s much more convenient to have them both in convenient PHP functions.

file_ext()

Returns only the file extension (without the period).

function file_ext($filename) {
    return preg_replace('/^.*\./', '', $filename);
}

Returns the file name, less the extension.

function file_ext_strip($filename){
    return preg_replace('/\.[^.]*$/', '', $filename);
}

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Igor Escobar says:

March 12, 2009 at 9:41 am

I test it using the regex pal and the result of the first function does’t work so well.

http://regexpal.com/?flags=&regex=(^.*.)&input=igor.escobar.jpg
Cory LaViska says:

March 14, 2009 at 4:38 pm

@Igor Escobar: Sorry! You were right, there was an escape issue so the backslashes weren’t appearing in the regex pattern. They work now :)
Rob C says:

June 19, 2009 at 12:16 pm

Very handy, and much more elegant than the ‘traditional’ explode() / strstr() / substr() etc. methods.
Bill Brown says:

September 20, 2009 at 8:58 pm

Of course, you could also just use PHP’s built-in functions for this:

<?php
function file_ext ($name)
{
$info = pathinfo($name);
return $info['extension'];
}
function file_ext_strip ($name)
{
$info = pathinfo($name);
return $info['filename'];
}

# DEMO
$filename = "/path/to/some.file";
echo file_ext($filename).’<br>’;
echo file_ext_strip($filename).’<br>’;
?>