正则表达式沮丧试图找到与模式匹配的文件名

Question

I suck at regex. I have a php function that will read through a directory of filenames on my server, and I am trying to pull out filename data from one specific filename, but am failing miserably. Here is what I have thus far:

$file = 'VERSION_3.7.1b.txt';
$VersionNumber = preg_match('#^(VERSION_)[^\s]*\.\.[^\s]+(\.(txt))#', $file);

I am trying to have the preg_match only return true for files that begin with 'VERSION_' and end with '.txt. The stuff in the middle may be any variety of numbers, letters, periods...and that is the part I want to return. So in this case, I want $VersionNumber to end up set as '3.7.1b'

Other filenames that would return something are like these:

VERSION_3.txt  ->  3
VERSION_3.7.txt  ->  3.7
VERSION_3.7e.1.txt  ->  3.7e.1
VERSION_2012.09.13.3.7.1b.txt  ->  2012.09.13.3.7.1b
VERSION_3.7.20120913.txt  ->  3.7.20120913

Any regex masters out there that can explain to me if I am even close? Thanks!

Answer 1

You'll want to pass a variable for $matches as well.

I simplified your RegExp. Try this:

$file = 'VERSION_3.7.1b.txt';
preg_match('/^VERSION_(.*?)\.txt/', $file, $matches);
echo $matches[1];