PHP substr used with preg_replace

Question

I have function:

function postNumberToLink($string) {
 return preg_replace('!\>\>\d+!', "<a href='#$0'><font color='red'>$0</font></a>", $string);
}

My questions:

• What's better (generally): Formatting string before putting it to db, or formatting clear text after querying it from database?

• I'd like to change every element compatibile with pattern ($0) in function above which means to remove first two characters (>>) and put the rest into href. I was trying to use substr on it, but it crashed. I also read about preg_replace_callback where I did put function as a second parameter and it also crashed even when I write inside the function the simpliest code. How can I make text like

"I'm replying to post no. >>21313123" to "I'm replying to post no. [href=21313123][red]>>21313123[/red][/href]" ?

Sorry for brackets[], but I can't figure out how do SO tags work.

Regards Matt

Answer 1

Your Questions

1. Keep it in your syntax in the database. This has several advantages:

   • You are not limited to HTML only. What if you make an API tomorrow that outputs JSON or XML?
   • You don't need to unparse and reparse it every time you need to edit.

2. You can use control groups in your regular expression:

   return preg_replace('!\>\>(\d+)!', "<a href='#$1'><font color='red'>$0</font></a>", $string);
   //                        ^   ^ Brackets!     ^^ First group        ^^ All match
   

Extra Points:

• Don't use <font> it's deprecated since before Jon Skeet had less than 100k reputation. Instead, use a class name on your links, and use CSS to style those:

  <a href="#" class="reply-to">