Using $ variables in preg_replace in PHP

Question

Ummm... how do I use variables in a call to preg_replace?

This didn\'t work:

foreach($numarray as $num => $text)
    {
        $patterns[] = \'/

        

Answer 1

Your replacement pattern looks ok, but as you've used single quotes in the matching pattern, your $num variable won't be inserted into it. Instead, try

$patterns[] = '/(.*?)\+'.$num.'(.*?)<\/ces>/';
$replacements[] = '$1<'.$text.'/>$2';

Also note that when building up a pattern from "unknown" inputs like this, it's usually a good idea to use preg_quote. e.g.

$patterns[] = '/(.*?)\+'.preg_quote($num).'(.*?)<\/ces>/';

Though I guess given the variable name it's always numeric in your case.