Question

I have a question in regexp –

$template = preg_replace("/\<\!\-\-\{(.+?)\}\-\-\>/s", "{\\1}", $template);

but I don’t know what the ‘1’ means, can anyone tell me about this? thanks all.

Answer 1

Simply the first matching group of your regex (in this case, it’s (.+?) which is inside {} in your regex), so that code replaces things like <!--{test}--> to {test}

as our good sir nomaD pointed in his comment below, it’s better to use $1 instead of \\1 in your replacement string

$template = preg_replace("/\<\!\-\-\{(.+?)\}\-\-\>/s", "{$1}", $template);
                                                         ^^
                                                         this