Question

im trying to get preg_replace to totally remove a string from a message

heres an example of a $message:

hello there john214

welcome to the site!

please get feel free to kick back and relax.

where john214 is a username outputted via the db

now i want to get rid of hello there john214 using preg_replace, however, my code is removing everything except for john214

heres my code:

$message = preg_replace('|hello there (.*?)|si', '', $message);

why is it not removing john214?

Answer 1

It might be because you are doing a non greedy approach. Try this:

$message = preg_replace('|hello there(.*)|si', '', $message);

This will get rid of EVERYTHING that goes after hello there (because of the S modifier). However, if what you want is get rid of everything in a single line that goes after hello there, you want to get rid of the s modifier as:

$message = preg_replace('|hello there(.*)|i', '', $message);

If you use the s modifier you are making the Dot metacharacter to match newlines, and that’s why the first regex will consume all what goes after hello there (even jumping to new lines).