On Wed, Jul 15, 2009 at 5:16 PM, Jan Kaliszewskizuo@chopin.edu.pl wrote:
16-07-2009 o 00:54 Chris Rebert firstname.lastname@example.org wrote:
You can fix that by just writing it as:
while True: SOME ACTIONS HERE if not CONDITION: break
Yeah, but it's not the same :) because eyes must look for the actual loop condition somewhere-within-the-loop (after all, "while True" is common idiom with large field of usage, not only in such situations...).
Another solution I invented for myself is to use object which once evaluates to True, then always to False, e.g.:
from itertools import chain, repeat class FirstTrue(object): def __init__(self): self._iter = chain([True], repeat(False)) def __nonzero__(self): # __bool__ for Py3k return next(self._iter)
first = FirstTrue() while first or CONDITION: SOME ACTIONS HERE
or, if we want to *evaluate* CONDITION also at first time:
first = FirstTrue() while CONDITION or first: SOME ACTIONS HERE
I usually do: FIRST = 1 while CONDITION or FIRST: FIRST = 0 SOME ACTIONS HERE
I use 1/0 instead of True/False because older Pythons loaded numeric constants faster than the names True/False (is that still the case?)
Wouldn't be nice to have such factory as built-in or in itertools?
Best regards, *j
-- Jan Kaliszewski email@example.com _______________________________________________ Python-ideas mailing list Pythonfirstname.lastname@example.org http://mail.python.org/mailman/listinfo/python-ideas