searching backwards in a string

Paul Rubin phr-n2002a at nightsong.com
Thu Feb 14 07:15:50 CET 2002


Skip Montanaro <skip at pobox.com> writes:
>     Paul> here 50000 and -1 are the starting and ending locations.
> 
>     Skip> If start > end isn't direction == -1 implied?
> 
>     Paul> Nope.  I tried it and it didn't search backwards.  
> 
> That wasn't quite what I was asking.  Let me ask it a slightly
> different way.  Presuming the behavior can be changed so that
> searching in reverse works, shouldn't the ordering of start and end
> be sufficient to indicate the direction of the search?

That might have been an ok way for the implementers to have originally
designed the re module, but they designed and documented a different
way instead.  Changing the behavior now of already-documented
arguments could break existing programs.  It's better to add a new arg
to preserve compatibility, and it's a cleaner design anyway to use a
separate arg.



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