groups method of the math object (was Re: Perl is worse!)

[Alex Martelli]

"Karl Ulbrich" <kulbrich at yahoo.com> wrote in message
news:20000730023357.A3193 at exeter.exeter.org...
    ...
> >     I don't see where I can tell it to pass something other than None on
a
> > match.  The docs I read, (not here) state that it /will/ return None on
a
> > no-match, not that it /can/ and that you can override it.
>
> I don't see it either (Alex?) in the library reference.  Personally

It's in 4.2.5 in the Library Reference I have here, "4.2.5 Match Objects"
to be precise:

groups ([default])
Return a tuple containing all the subgroups of the match, from 1 up to
however many groups are in the pattern. The default argument is used for
groups that did not participate in the match; it defaults to None.

> I thought both the 'int(x or 0)' approach and the function Alex suggested
> were good ways to establish problem-specific default values, especially
> since '0' isn't always an apprpriate default.

I agree, and int(x or whatever) is more general since it works with any
x that is a possibly-empty-sequence-of-digits (the 'whatever' default
will more often be 1, I think; if you specify you want something, without
explicitly specifying how many of those somethings you want, it's more
natural to default to you wanting one of them, than none).


Alex