PHP - Translating Asp Instructions Into Php?

Hoping someone can help me on this, but I had some help on getting this code (or part of it) to finally work the way I wanted it, however, there are a few end-user issues with it now.

What this code does is disables the user(s) from posting any kind of links (www.example.com or example.com). However, now I'm trying to....expand it a little I guess.

Here is the current code:
Code: [Select]
if (stristr($pagetext, 'http://') OR stristr($pagetext, 'www.') OR stristr($pagetext,'@') OR stristr($pagetext, '[URL') OR stristr($pagetext, '[url') OR stristr($pagetext, '[IMG') OR stristr($pagetext, '[img') OR preg_match("#[a-z0-9]([-a-z0-9]+)?(\.[a-z]{2,3})?(\.[a-z]{2,4})#i", $pagetext))
            {
                more code here
            }
Now, I KNOW what most of that code does, but what I need, is what exactly this code does:
Code: [Select]
preg_match("#[a-z0-9]([-a-z0-9]+)?(\.[a-z]{2,3})?(\.[a-z]{2,4})#i", $pagetext)Can anyone break this down and tell me what exactly does what?

Thanks in advance

Hello,

I am writing a CMS for a sports organization league. One of my pages grabs values from the database using only the current week. What I want to do is when the admin enters in a game date, I want it to automatically find the week number for the date they entered. I haven't been able to find anything online that works for me.

Any help would be great!
Thanks 

I'm helping a friend in developing a project for our alma mater. And its based on this paper: An Enhanced Indoor Positioning Method Based on Wi-Fi RSS Fingerprinting

So far 80% of the web app is finished except for the algorithm (We have no experience with algorithms to source code translations) that needs to be implemented in the website. Inside this paper there is this algorithm that the proponents of the research used. (attached as screenshot).

The algorithm was converted to code by using MATLAB, but we are trying to use PHP with our project. Based on the pseudo code the calculation of the Euclidean Distance is the core of it. Can anyone help us with the translation just to get it started.