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From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.python
Subject: Re: Pythonic infinite for loop?
References: <mailman.377.1302833455.9059.python-list@python.org>
Date: Fri, 15 Apr 2011 00:24:25 -0700
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:3246

Chris Angelico <rosuav@gmail.com> writes:
That loop will exit at the first gap in the sequence.  If that's what
you want, you could try (untested):

   from itertools import takewhile

   seq = takewhile(lambda n: ('Keyword%d'%n) in dct, count(1))
   lst = map(dct.get, seq)

This does 2 lookups per key, which you could avoid by making the code
uglier (untested):

   sentinel = object()
   seq = (dct.get('Keyword%d'%i,sentinel) for i in count(1))
   lst = list(takewhile(lambda x: x != sentinel, seq))