Concerning Regular Expressions

[Terry Reedy]

"Tempo" <bradfordh at gmail.com> wrote in message 
news:1138595614.254959.70740 at o13g2000cwo.googlegroups.com...
> Whoops. I've got another tid-bit to tack onto this post. What kind of
> value does this expression return:
>
> re.sub(r'^R0 -', line)
>
>
> Does it return a '1' if successful and a '0' if not successful?

Start up an interactive interpreter window, try it, and see.
Such discoveries are one thing the interactive mode is designed for.