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regular expression : the dollar sign ($) work with re.match() or re.search() ？

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  regular expression :  the dollar sign ($) work with re.match() or re.search()  ？ iMath <redstone-cold@163.com> - 2012-09-26 00:38 -0700
    Re: regular expression :  the dollar sign ($) work with re.match() or re.search() Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-09-26 10:48 +0300
      Re: regular expression : the dollar sign ($) work with re.match() or re.search() Chris Angelico <rosuav@gmail.com> - 2012-09-26 17:57 +1000
      Re: regular expression :  the dollar sign ($) work with re.match() or re.search() Alister <alister.ware@ntlworld.com> - 2012-09-26 15:47 +0000
        Re: regular expression :  the dollar sign ($) work with re.match() or re.search() Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2012-09-26 19:29 +0300
    Re: regular expression : the dollar sign ($) work with re.match() or re.search() ？ Peter Otten <__peter__@web.de> - 2012-09-26 10:33 +0200
    RE: regular expression :  the dollar sign ($) work with re.match() or re.search()  ？ "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-09-28 18:07 +0000
    Re: regular expression : the dollar sign ($) work with re.match() or re.search() ？ Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-28 12:32 -0600
    Re: regular expression :  the dollar sign ($) work with re.match() or re.search()  ？ iMath <redstone-cold@163.com> - 2013-01-07 01:45 -0800
      Re: regular expression :  the dollar sign ($) work with re.match() or re.search()  � Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-07 09:54 +0000

#30152 — regular expression : the dollar sign ($) work with re.match() or re.search() ？

I only know  the dollar sign ($) will match a pattern from the
end of a string,but which method does it work with ,re.match() or re.search()  ？

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#30155 — Re: regular expression : the dollar sign ($) work with re.match() or re.search()

iMath writes:

> I only know the dollar sign ($) will match a pattern from the end of
> a string, but which method does it work with, re.match() or
> re.search()

It works with both. With re.match, the pattern has to match at the
start of the string _and_ the $ has to match the end of the string (or
a line); re.search scans the string until it finds a suitable start.

What was the weird character that you used as a question mark? I
removed them because they confuse the newsreader I use.

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#30156 — Re: regular expression : the dollar sign ($) work with re.match() or re.search()

On Wed, Sep 26, 2012 at 5:48 PM, Jussi Piitulainen
<jpiitula@ling.helsinki.fi> wrote:
> What was the weird character that you used as a question mark? I
> removed them because they confuse the newsreader I use.

It appears to be Unicode Character 'FULLWIDTH QUESTION MARK' (U+FF1F).
Normally I'd be inclined to simply use U+003F instead, but hey, it's a
question mark still.

ChrisA

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#30217 — Re: regular expression : the dollar sign ($) work with re.match() or re.search()

On Wed, 26 Sep 2012 10:48:00 +0300, Jussi Piitulainen wrote:

> iMath writes:
> 
>> I only know the dollar sign ($) will match a pattern from the end of a
>> string, but which method does it work with, re.match() or re.search()
> 
> It works with both. With re.match, the pattern has to match at the start
> of the string _and_ the $ has to match the end of the string (or a
> line); re.search scans the string until it finds a suitable start.
> 
> What was the weird character that you used as a question mark? I removed
> them because they confuse the newsreader I use.

It shows fine in my news reader, perhaps you should consider changing to 
one that works properly (btw I am using pan on a fedora 17 netbook)



-- 
Q: Why is Microsoft's Product Support a failure?
A: Because Microsoft needs a Support Group instead.

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#30226 — Re: regular expression : the dollar sign ($) work with re.match() or re.search()

Alister writes:
> On Wed, 26 Sep 2012 10:48:00 +0300, Jussi Piitulainen wrote:
> 
> > iMath writes:
> > 
> >> I only know the dollar sign ($) will match a pattern from the end
> >> of a string, but which method does it work with, re.match() or
> >> re.search()
> > 
> > It works with both. With re.match, the pattern has to match at the
> > start of the string _and_ the $ has to match the end of the string
> > (or a line); re.search scans the string until it finds a suitable
> > start.
> > 
> > What was the weird character that you used as a question mark? I
> > removed them because they confuse the newsreader I use.
> 
> It shows fine in my news reader, perhaps you should consider changing to 
> one that works properly (btw I am using pan on a fedora 17 netbook)

I was just curious why anyone would use anything other than the ASCII
question mark as an ordinary question mark when writing in English in
a newsgroup.

The post had this:

0000520 61 72 63 68 28 29 20 20 ef bc 9f 0a
          a   r   c   h   (   )  sp  sp   o   <  us  nl

od is showing (ef bc 9f) as (o < us) but since they are not individual
characters anyway, never mind that. Google tells me (ef bc 9f) is
UTF-8 for U+FF1F FULLWIDTH QUESTION MARK, so now I basically have my
answer as to what it is, though still not as to why one would use it.

The ordinary question mark would look like this:

0000000 61 72 63 68 28 29 20 3f 0a
          a   r   c   h   (   )  sp   ?  nl

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#30163 — Re: regular expression : the dollar sign ($) work with re.match() or re.search() ？

iMath wrote:

> I only know  the dollar sign ($) will match a pattern from the
> end of a string,but which method does it work with ,re.match() or
> re.search()  ？

Why not try it out in the interactive interpreter? Here's the "deluxe 
version":

>>> def demo(pattern="mid$", texts=["start mid end", "start mid", "mid end", 
"mid"], matchers=[re.match, re.search]):
...     print "pattern:", pattern
...     for text in texts:
...             for matcher in matchers:
...                     name = matcher.__name__
...                     print u"\N{CHECK MARK}" + name if matcher(pattern, 
text) else (" "*(len(name)+1)),
...             print repr(text)
... 
>>> demo()
pattern: mid$
               'start mid end'
       ✓search 'start mid'
               'mid end'
✓match ✓search 'mid'

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#30421

iMath wrote:
> Sent: Wednesday, September 26, 2012 2:39 AM
> To: python-list@python.org
> Subject: regular expression : the dollar sign ($) work with re.match() or re.search() ？
> 
> I only know  the dollar sign ($) will match a pattern from the
> end of a string,but which method does it work with ,re.match() or re.search()  ？


You can try this on the interactive interpreter.
>>> re.match('hi$', 'xihi')
>>> re.search('hi$', 'xihi')
<_sre.SRE_Match object at 0x13FF7100>

Although, I think match does not work since match
only starts searching at the start of the string
while search looks for the pattern anywhere in the string.

>>> re.match('x.hi$', 'xihi')
<_sre.SRE_Match object at 0x15693BF0>

I guess you can consider re.match's pattern to be 
prefixed with '^'.

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#30424 — Re: regular expression : the dollar sign ($) work with re.match() or re.search() ？

On Fri, Sep 28, 2012 at 12:07 PM, Prasad, Ramit
<ramit.prasad@jpmorgan.com> wrote:
> I guess you can consider re.match's pattern to be
> prefixed with '^'.

You can in this case, but they're not equivalent in multi-line mode:

>>> re.match('^two', 'one\ntwo', re.M)
>>> re.search('^two', 'one\ntwo', re.M)
<_sre.SRE_Match object at 0x0475BFA8>

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#36334

在 2012年9月26日星期三UTC+8下午3时38分50秒，iMath写道：
> I only know  the dollar sign ($) will match a pattern from the
> 
> end of a string,but which method does it work with ,re.match() or re.search()  ？

I thought re.match('h.$', 'hbxihi') will match ‘hi’ ,but it does not .so why ?

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#36338 — Re: regular expression : the dollar sign ($) work with re.match() or re.search() �

On Mon, 07 Jan 2013 01:45:58 -0800, iMath wrote:

> 在 2012年9月26日星期三UTC+8下午3时38分50秒，iMath写道：
>> I only know  the dollar sign ($) will match a pattern from the
>> 
>> end of a string,but which method does it work with ,re.match() or
>> re.search()  ？
> 
> I thought re.match('h.$', 'hbxihi') will match ‘hi’ ,but it does not .so
> why ?


re.match only matches at the *start* of the string, so "h.$" tries to 
match:

* start of string
* literal h
* any character
* end of string


You want re.search, which will search the entire string and match "hi" at 
the end of the string.


-- 
Steven

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