Variables in String

I want to construct a string like below:

“this is a $atest, testing $bstring…”

$a and $b are variables, can I tell PHP to separate them from following string in some way? I know I can achieve this by concatenating several sub-strings, but it would be much more convenient to use the above format in my case.

Thanks!

Have a read through the section on variable parsing in strings, it should give you the info you need. (:

Thanks for the link, {} did the trick.