Preg_place reg expression help

[All4172]

What I"m wanting to do is to take:

 

/q?s=ABCDE

 

and to change it to

 

/mydirectory/ABCDE.php

 

Sometimes the file is 3 letters sometimes 4 and other times five.  What is the correct regex to use in a preg_replace / str_replace function?

[effigy]

#/q\?s=([A-Z]{3,5})#

[All4172]

That gets me to match it...but how do I phrase it in order to keep the letters though? 

 

In the example above I need to somehow keep the ABCDE in order to apend it with the .php on the end.

[effigy]

The parentheses capture the information into backreference \1.

 

<pre>
<?php
$str = '/q?s=ABCDE';
echo preg_replace('#/q\?s=([A-Z]{3,5})#', '/mydirectory/\1.php', $str);
?>
</pre>