Question

I am making a system that takes all optional subjects from a education and puts it in a database. This works fine.
Now I want to make sure if you choose “Finance A” you can’t choose “Finance C”, I’m trying to do this with preg_replace as the subject is a array. But it keeps giving me an error:

Delimiter must not be alphanumeric or backslash

Now here is some of the code:

if
(
    preg_replace("/" + $name_without_level + " (A|B|C)/", "", $andre_fag) 
        == $andre_fag
    || preg_replace("/" + $name_without_level + " (A|B|C)/", "", $andre_fag2)
        == $andre_fag2
){

The variable $name_without_level gives the Subject name without A, B or C, the Level.

How to fix the error? I have tried everything I can think of.

Answer 1

Imagine $name_without_level is just "Finance / Markets". Imagine what happens to your regular expression.

Use preg_quote^Docs to ensure you’re looking for the right string literally and you don’t destroy your regular expression:

$pattern = sprintf('/%s (A|B|C)/', preg_quote($name_without_level));
if
(
    preg_replace($pattern, "", $andre_fag) == $andre_fag
    || preg_replace($pattern, "", $andre_fag2) == $andre_fag2
){

This does not mean that this is your only problem with the code. You need to do error checking to actually locate the error.