preg_replace is replacing $ signs

Question

I have the following piece of code which replaces "template markers" such as %POST_TITLE% with the contents of a variable called $post_title.

function replaceTags( $template, $newtext ) {
    $template = preg_replace( '/%MYTAG%/', $newtext, $template );
    return $template;
}

The issue is that when $post_full has a '$' in it, the returned result has this removed. For example:

$template = "Replace this: %MYTAG";
$newtext = "I earn $1,000,000 a year";

print replaceTags( $template, $newtext );

// RESULT
Replace this: I earn ,000,000 a year";

I know this has something to do with not properly escaping the $1 in the $newtext. I have tried using preg_quote() but it doesn't have the desired effect.

Answer 1

According to preg_replace manual, preg_replace() treats this ($1) as backreference.
(and not a "callback syntax" as mentionned in the comments of the preg_replace manual page.
Thank you Jan Goyvaerts).

$newtext = preg_replace("!" . '\x24' . "!" , '\\\$' , $newtext );

should take care of your '$' sign

Answer 2

Ummm, since you aren't actually using a regexp there, why not just use str_replace? It'll be faster and you won't have weird issues like this.