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

Variables will only be expanded in strings declared with double quotes. So either use double quotes:

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

Or use string concatenation:

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

You should also take a look at preg_quote if your variables may contain regular expression meta characters.