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Re: Python's re module and genealogy problem

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On 2014-06-11 13:23, BrJohan wrote:
> For some genealogical purposes I consider using Python's re module.
>
> Rather many names can be spelled in a number of similar ways, and in order to
> match names even if they are spelled differently, I will build regular
> expressions, each of which is supposed to match  a number of similar names.
>
> I guess that there will be a few hundred such regular expressions covering most
> popular names.
>
> Now, my problem: Is there a way to decide whether any two - or more - of those
> regular expressions will match the same string?
>
> Or, stated a little differently:
>
> Can it, for a pair of regular expressions be decided whether at least one string
> matching both of those regular expressions, can be constructed?
>
> If it is possible to make such a decision, then how? Anyone aware of an
> algorithm for this?

And if that isn't the best straight line for the old saying, I don't know what is.

   http://en.wikiquote.org/wiki/Jamie_Zawinski

Anyways, to your new problem, yes it's possible. Search for "regular expression 
intersection" for possible approaches. You will probably have to translate the 
regular expression to a different formalism or at least a different library to 
implement this.

Consider just listing out the different possibilities. All of your regexes 
should be "well-behaved" given the constraints of the domain (tightly bounded, 
at least). There are tools that help generate matching strings from a Python 
regex. This will help you QA your regexes, too, to be sure that they match what 
you expect them to and not match non-names.

   https://github.com/asciimoo/exrex

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco

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Python's re module and genealogy problem BrJohan <brjohan@gmail.com> - 2014-06-11 14:23 +0200
  Re: Python's re module and genealogy problem Robert Kern <robert.kern@gmail.com> - 2014-06-11 14:26 +0100
    Re: Python's re module and genealogy problem Mark H Harris <harrismh777@gmail.com> - 2014-06-11 09:08 -0500
  Re: Python's re module and genealogy problem Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2014-06-11 15:55 +0200
  Re: Python's re module and genealogy problem Michael Torrie <torriem@gmail.com> - 2014-06-11 09:34 -0600
  Re: Python's re module and genealogy problem Nick Cash <nick.cash@npcinternational.com> - 2014-06-11 16:21 +0000
  Re: Python's re module and genealogy problem Simon Ward <simon@bleah.co.uk> - 2014-06-11 18:21 +0100
  Re: Python's re module and genealogy problem Vlastimil Brom <vlastimil.brom@gmail.com> - 2014-06-11 20:09 +0200
  Re: Python's re module and genealogy problem BrJohan <brjohan@gmail.com> - 2014-06-13 17:17 +0200
    Re: Python's re module and genealogy problem Peter Otten <__peter__@web.de> - 2014-06-13 18:26 +0200
    Re: Python's re module and genealogy problem Dan Sommers <dan@tombstonezero.net> - 2014-06-14 05:14 +0000
  Re: Python's re module and genealogy problem Tony the Tiger <tony@tiger.invalid> - 2014-06-14 08:35 +0000

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