How to substitute a variable in an address with Curl?

Question

PHP

Good night, tell me how to substitute your variable in the line with the curl address
, there is a code:

$add='user123'
$curl->page('https://www.site.com/');

how to substitute the $add variable in the request so that curl goes to https://www.site.com/user123/
Thanks for the reply

Answer 1

in its original form:
there are a bunch of variations on the theme, ranging from sprintf to smarter handling of urlencode - because the moment $add starts to contain spaces or special characters, your code will crash.
And there is generally space like http_build_query