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Re: Question about metacharacter '*'

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On Sun, Jul 6, 2014 at 4:51 AM,  <rxjwg98@gmail.com> wrote:
> Hi,
>
> I just begin to learn Python. I do not see the usefulness of '*' in its
> description below:
>
>
>
>
> The first metacharacter for repeating things that we'll look at is *. * doesn't
> match the literal character *; instead, it specifies that the previous character
> can be matched zero or more times, instead of exactly once.
>
> For example, ca*t will match ct (0 a characters), cat (1 a), caaat (3 a
> characters), and so forth.
>
>
>
> It has to be used with other search constraints?

(BTW, this is a regexp question, not really a Python question per se.)

That's usually when it's useful, yeah. For example, [0-9] matches any
of the characters 0 through 9. So to match a natural number written in
decimal form, we might use the regexp [0-9][0-9]*, which matches the
strings "1", "12", and "007", but not "" or "Jeffrey".

Another useful one is `.*` -- `.` matches exactly one character, no
matter what that character is. So, `.*` matches any string at all.

The power of regexps stems from the ability to mix and match all of
the regexp pieces in pretty much any way you want.

-- Devin

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Thread

Question about metacharacter '*' rxjwg98@gmail.com - 2014-07-06 04:51 -0700
  Re: Question about metacharacter '*' Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-07-06 05:09 -0700
    Re: Question about metacharacter '*' rxjwg98@gmail.com - 2014-07-07 11:51 -0700
      Re: Question about metacharacter '*' Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-07-07 13:27 -0700
      Re: Question about metacharacter '*' Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-07-07 22:50 +0100
  Re: Question about metacharacter '*' MRAB <python@mrabarnett.plus.com> - 2014-07-06 16:32 +0100
  Re: Question about metacharacter '*' Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-07-06 08:50 -0700
    Re: Question about metacharacter '*' Rick Johnson <rantingrickjohnson@gmail.com> - 2014-07-06 09:24 -0700
      Re: Question about metacharacter '*' Rick Johnson <rantingrickjohnson@gmail.com> - 2014-07-06 09:32 -0700
      Re: Question about metacharacter '*' Roy Smith <roy@panix.com> - 2014-07-06 12:47 -0400
        Re: Question about metacharacter '*' Rick Johnson <rantingrickjohnson@gmail.com> - 2014-07-06 10:38 -0700
          Re: Question about metacharacter '*' Rick Johnson <rantingrickjohnson@gmail.com> - 2014-07-06 10:58 -0700

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