Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #74007

Re: Question about metacharacter '*'

Path csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!rt.uk.eu.org!newsfeed.xs4all.nl!newsfeed2a.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path <jeanpierreda@gmail.com>
X-Original-To python-list@python.org
Delivered-To python-list@mail.python.org
X-Spam-Status OK 0.003
X-Spam-Evidence '*H*': 0.99; '*S*': 0.00; 'python.': 0.02; 'matches': 0.07; 'subject:Question': 0.07; 'string': 0.09; 'character,': 0.09; 'literal': 0.09; 'matched': 0.09; 'cc:addr:python-list': 0.11; 'python': 0.11; 'times,': 0.14; 'useful,': 0.14; 'a),': 0.16; 'forth.': 0.16; 'once.': 0.16; 'subject:skip:m 10': 0.16; 'all.': 0.16; 'wrote:': 0.18; 'pieces': 0.19; 'written': 0.21; 'cc:addr:python.org': 0.22; 'specifies': 0.24; 'question': 0.24; 'cc:2**0': 0.24; 'header:In-Reply-To:1': 0.27; 'am,': 0.29; 'character': 0.29; "doesn't": 0.30; 'characters': 0.30; 'mix': 0.30; 'message-id:@mail.gmail.com': 0.30; 'usually': 0.31; 'decimal': 0.31; 'another': 0.32; 'but': 0.35; 'received:google.com': 0.35; 'really': 0.36; 'useful': 0.36; 'hi,': 0.36; 'example,': 0.37; 'so,': 0.37; 'form,': 0.38; 'question,': 0.38; 'previous': 0.38; 'ability': 0.39; 'is.': 0.60; 'matter': 0.61; 'first': 0.61; 'more': 0.64; 'to:addr:gmail.com': 0.65; 'natural': 0.68; 'below:': 0.68; 'jul': 0.74; 'power': 0.76; 'regexp': 0.84
DKIM-Signature v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=U7R/EbOho6nthLAgGTjawcDK/i7oNtT/49I30IQCWGM=; b=cckNRhnhwGEEnGvFn1mi9J/EB7jFPuohlAuJysTbhI2i0bKL72491OiGr+o4nVItD9 fXOekGSn3J9Gd2+C/k0bJNeUpc1aEWthD98GursO8uLNu5pv7XzOyIHgNLiqtXpzFZu5 fOexpviN2ZeAd1hu8qm9LJMLviuiYUFJDrmUuepSc7VmodG3jMtj9r7h7NCq8zqefYfD 8Lf+aJz29yeVi2D2RHudClx9KMZfrJub/5ncOauqIMBkoKvrUquAFrym59SjosPmwFVI 4t9Rb0dtvU1bj48TtG5ub2nNPuhidMS8j1GSBCK7NUd0fO75kktiwoADH7ebYcFe9bup t5sA==
X-Received by 10.140.18.243 with SMTP id 106mr34931987qgf.105.1404648637815; Sun, 06 Jul 2014 05:10:37 -0700 (PDT)
MIME-Version 1.0
In-Reply-To <3f7ecf04-b881-4e79-aa59-893580090468@googlegroups.com>
References <3f7ecf04-b881-4e79-aa59-893580090468@googlegroups.com>
From Devin Jeanpierre <jeanpierreda@gmail.com>
Date Sun, 6 Jul 2014 05:09:57 -0700
Subject Re: Question about metacharacter '*'
To rxjwg98@gmail.com
Content-Type text/plain; charset=UTF-8
Cc "comp.lang.python" <python-list@python.org>
X-BeenThere python-list@python.org
X-Mailman-Version 2.1.15
Precedence list
List-Id General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe <https://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive <http://mail.python.org/pipermail/python-list/>
List-Post <mailto:python-list@python.org>
List-Help <mailto:python-list-request@python.org?subject=help>
List-Subscribe <https://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups comp.lang.python
Message-ID <mailman.11536.1404648646.18130.python-list@python.org> (permalink)
Lines 34
NNTP-Posting-Host 2001:888:2000:d::a6
X-Trace 1404648646 news.xs4all.nl 2924 [2001:888:2000:d::a6]:57087
X-Complaints-To abuse@xs4all.nl
Xref csiph.com comp.lang.python:74007

Show key headers only | View raw

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

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

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

csiph-web