Question

$end = preg_replace($pattern, $replacement, $str);

How can I make the replacement string $replacement vary with each match in $str? For example, I want to replace each matched string with an associated image. Something about callbacks… right?

Answer 1

Yes, something with callbacks. Specifically preg_replace_callback, which makes repeated calls redundant. For a list of things to replace:

 $src = preg_replace_callback('/(thing1|thing2|thing3)/', 'cb_vars', $src);

Where the callback can do some form of lookup or conversion:

 function cb_vars($m) {
     return strtoupper($m[1]);
 }

Likewise can you do that inline with the normal preg_replace and the /e modifier.