[Gllug] matching strings in python

[dudes dudes]

thanks very much Stuart for your explanation. Kind of you 

> Date: Sun, 2 Oct 2011 16:22:05 +0100
> From: stuart at sjsears.com
> To: gllug at gllug.org.uk
> Subject: Re: [Gllug] matching strings in python
> 
> On 02/10/2011 11:08, dudes dudes wrote:
> >
> >
> >  >
> >  > RTFM :)
> >
> > TFM has been Read b4 starting the project :P
> 
> well, that's very good. Did you go back to it when your pattern wasn't 
> working?
> 
> >  > http://docs.python.org/library/re.html#matching-vs-searching
> >  >
> >  > specifically:
> >  > where are these numbers on each line? Are they at the start? if not,
> >  > re.match won't find them without a preceding wildcard.
> >
> > yes there are one each line and at the start of each
> 
> so your pattern can be simpler.
> 
> >  > Also, there's no need for the 'this=...' bit, unless you actually feel
> >  > you need the variable.
> >
> > yes I need "this" as variable even though it has a different variable
> > name in the source code.
> >
> >  > Something like the following
> >  >
> >  > for line in open('filename'):
> >  > if re.search('1000[01]', line):
> >  > print line
> >
> >
> >  > is more likely to succeed
> >
> > YES True, but there are 10.000 different digit numbers, but I only need
> > to find 10 numbers .. such as 10000, 10001, 1286, 3412, 3512, 456,
> > 653,,,etc and they are different. Therefore I need to retrieve one out
> > of these 10 numbers !
> 
> The regex pattern I gave you matches '10000' and '10001', which was all 
> you asked for.
> Your response above sort-of suggests that you don't realise this?
> 
> It would be fairly trivial to extend it to match all the numbers you 
> want. Something like...
> 
> re.match('^(1000[01]|653|1286|...)', line)
> 
> (this time being specific that the numbers are at the beginning of each 
> line.)
> 
> another point: how many lines are there in the file?
> For more than a small number it is arguably more efficient to do this:
> 
> numpatt = re.compile(PATTERN)
> for line in this:
>      if numpatt.match(line):
>          print line
> 
> Or you essentially re-run the re.compile process for every line.
> 
> [snip]
> > yes True but using DrPython as an editor won't let you to save the code
> > if you have syntax issues.
> 
> We don't know that.
> 
> >  > This example was fairly trivial, but if you are asking for help with
> >  > code like this, it would help if you actually post working excerpts from
> >  > it. Or excerpts that throw the errors you are asking about.
> >
> > agree and thank you :)
> 
> Regards,
> 
> Stuart
> -- 
> Stuart Sears RHCA etc.
> "It's today!" said Piglet.
> "My favourite day," said Pooh.
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