PHP Function To Get A File Extension From A String

This looks really useful, thanks.

Why reinvent the wheel? We have good ol’ pathinfo() :
http://hu2.php.net/manual/en/function.pathinfo.php

Array
(
[dirname] => .
[basename] => some.file.extension
[extension] => extension
[filename] => some.file
)

I came up with this snippet to get the file extension as well, using array functions:

… and it got cut out. Here’s the function, without tags:

function get_file_extension($file_name) {
return end(explode(‘.’,$file_name));
}

As mentioned by ochronus the following code does the exact same thing:

$file = ‘/tmp/test.php’;
echo pathinfo($file, PATHINFO_EXTENSION);

or we can do it via end(explode(‘.’, “filename.ext)); easily

File extension from path:

function f_extension($fn){
$str=explode(‘/’,$fn);
$len=count($str);
$str2=explode(‘.’,$str[($len-1)]);
$len2=count($str2);
$ext=$str2[($len2-1)];
return $ext;
}

$extesnion=f_extension(“files/file.jpg”); // returns jpg

Try & enjoy!

What happens when you try to get the extension of “/etc/init.d/README” with the explode method?

Just use the pathinfo().

@Jorge: Either way works, and it just ends up being a matter of preference. You have to consider how this function will usually be used on a web application; it will be grabbing the extension and making sure it’s an allowed extension for upload. Thus, the explode method would return something that doesn’t match a valid extension (like your README example), and the file upload would get declined.

If you’re building a file explorer on the web, sure, use pathinfo(); that’s common sense. If you’re building a web app that takes uploads, then I can’t imagine the explode method would not be faster than pathinfo.

Thanks for sharing !

@crivion: please explain it with example

end(explode(‘.’, “filename.ext));,
explain how does it work