Question

As an example I’ll use this line:

/*! jQuery v1.7.1 jquery.com | jquery.org/license */

how would I use preg_match to find and isolate into a $version variable the 1.7.1?

Taking into account that the version number in that string will change dynamically without notice.

so in plain English it would sound like:

find the term 'jQuery v' and grab the following characters up until a space is found

Answer 1

Here’s an interactive php session for you:

php > $haystack = "/*! jQuery v1.7.1 jquery.com | jquery.org/license */";
php > preg_match('/jQuery v([^ ]*)/', $haystack, $matches);
php > print_r($matches);
Array
(
    [0] => jQuery v1.7.1
    [1] => 1.7.1
)

As you can see, the first match group contains your version number.