python for this C: "if ((a = b(c)) != NULL)"

[David Carson]

"Mark McEahern" <marklists at mceahern.com> wrote in message news:<mailman.1021328064.29854.python-list at python.org>...
> [David Carson]
> > So, how do I do this in Python, since I want to avoid running method
> > b() twice in the case where I want to use 'a' later?  In other words,
> > I don't want to do:
> > 
> >   if b(c):
> >     a = b(c)
> >     use a here ...
> 
> a = b(c)
> if a:
>   ...
> 
> // m


OK, so I wasn't quite clear in my original post.  I got four fine
answers like this one -- that is how I do it too.

They lack the other criterion that makes me use this style in C in the
first place -- brevity.  I choose the C syntax in the header because I
can save a line _and_ it is as clear and readable as the alternative
of doing it on two lines (as all these solutions suggest).  I would
not choose it if it was not readable.

So, I'll ask again: How do I do the equivalent in Python so that it is
both clear and concise?

Cheers,
David