substr to get file extension

[DKY]

I have the file and extension stored in a database and would like to know if there's something out there like substr but only backwards or even strchr but backwards? I want to get the extension of a file and right now i'm doing this

If (strchr ( $Row["File"], "." ) == ".pdf")

but if someone uploads a file with .'s in it then it doesn't work.

[notepad_coder]

Only thing I can think of is doing:

function getExt($file) {
    $tmp = explode(".", $file);
    return $tmp[(count($tmp) - 1)];
}
if (getExt($row['file']) == "pdf") {
} 

[logic_earth]

strrchr
http://www.php.net/manual/en/function.strrchr.php

Only thing I can think of is doing:
[php]
function getExt($file) {
$tmp = explode(".", $file);
return $tmp[(count($tmp) - 1)];
}
if (getExt($row['file']) == "pdf") {
}

$ext = end(explode('.', $file)); 

[php_daemon]

if (substr($Row["File"],-4,4) == ".pdf") 

or pathinfo

Edit:

this place is crowded

[notepad_coder]

I would have said pathinfo() but you can't do that, can you? Since the filename is a string returned from the database...

[php_daemon]

And why not? What difference does it make where does it come from?

[notepad_coder]

I just thought the path of the file any everything had to be there to do it. Learn something new every day.

[DKY]

$ext = end(explode('.', $file));
works beautifully, thanks

[Crowe]

$ext = end(explode('.', $file));
works beautifully, thanks

What if the file is my.little.file.txt ?

It's a valid file, but you won't get the extension. Either validate that the file is in [A-Za-z0-9] or use the earlier methods in this post. The explode method will work, it's just not bullet proof.

[Mike Borozdin]

If you want to use substr(), use this code:

function getFileExt($file) 
    {
        $i = 0;
        $ext = '';
        while (($pos = strpos($file, '.', $i)) !== false) {
            $ext = substr ($file, $pos + 1);
            $i++;
        } 
        return $ext;
    } 

[abb]

$a = pathinfo('file/with/path/filename.tar.gz');
$b = pathinfo('just_filename.tar.gz');
echo $a['extension']; // result is "gz"
echo $b['extension']; // result is "gz"

[logic_earth]

What if the file is my.little.file.txt ?

It's a valid file, but you won't get the extension. Either validate that the file is in [A-Za-z0-9] or use the earlier methods in this post. The explode method will work, it's just not bullet proof.

If the file is "my.little.file.txt" #ext = end(explode('.', 'my.little.file.txt'); will return "txt" because it will be the end of an array.

Also using pathinfo is recommend, I;m just defending the method i previously told which does fully work.

$ext = pathinfo($file, PATHINFO_EXTENSION); // PHP 5.2 Syntax 

[logic_earth]

If you are not on PHP 5 but would like to use its syntax

if (!defined('PATHINFO_DIRNAME')) {
    define('PATHINFO_DIRNAME', 1);
}

if (!defined('PATHINFO_BASENAME')) {
    define('PATHINFO_BASENAME', 2);
}

if (!defined('PATHINFO_EXTENSION')) {
    define('PATHINFO_EXTENSION', 4);
}

if (!defined('PATHINFO_FILENAME')) {
    define('PATHINFO_FILENAME', 8);
}

function ppathinfo($path, $option = null) {
    $path = pathinfo($path);

    switch ($option) {
        case PATHINFO_DIRNAME:
            return $path['dirname'];
            break;
        case PATHINFO_BASENAME:
            return $path['basename'];
            break;
        case PATHINFO_EXTENSION:
            return $path['extension'];
            break;
        case PATHINFO_FILENAME:
            return $path['filename'];
            break;
        default:
            return $path;
            break;
    }
} 

[Crowe]

If the file is "my.little.file.txt" #ext = end(explode('.', 'my.little.file.txt'); will return "txt" because it will be the end of an array.

Also using pathinfo is recommend, I;m just defending the method i previously told which does fully work.

$ext = pathinfo($file, PATHINFO_EXTENSION); // PHP 5.2 Syntax 

You're right. I didn't catch the "end" part in your code!

[barbara1712]

Try for this code

$file_extension = strtolower(substr(strrchr($file,"."),1));

And let me know

[stereofrog]

If (strchr ( $Row["File"], "." ) == ".pdf")

if(preg_match('/\.pdf$/D', $Row["File"]))...