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Created on 2006-08-28 17:38 by georg.brandl, last changed 2022-04-11 14:56 by admin. This issue is now closed.
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| File name | Uploaded | Description | Edit | |
| set-peepholer.c | georg.brandl, 2006-08-28 17:38 | #1 | ||
| Messages (5) | |||
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| msg51000 - (view) | Author: Georg Brandl (georg.brandl) *  |
Date: 2006-08-28 17:38 | |
Like "for x in tuple_or_list", this patch rewrites "for x in set" to use a constant frozenset. |
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| msg51001 - (view) | Author: Guido van Rossum (gvanrossum) * |
Date: 2006-08-29 18:24 | |
Logged In: YES
user_id=6380
Um, "for x in [1,2,3]" doesn't get any treatment. What would
be the point of writing "for x in {1,2,3}" anyway?
I'd rather reject this as premature optimization.
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| msg51002 - (view) | Author: Georg Brandl (georg.brandl) * |
Date: 2006-08-29 19:08 | |
Logged In: YES user_id=849994 Argh. Like in the py3k mail, I confusedly interchanged "for x in set" and "if x in set". if x in [1,2,3] does get special treatment, and optimizing the "in" test does make sense. |
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| msg51003 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2006-08-29 21:26 | |
Logged In: YES
user_id=80475
This implementation too simplistic, you need to use a
subclass of frozenset that overrides the __contains__()
method to return False when the argument is not hashable.
Otherwise, you end-up with a semantic change for:
x = {}
if x in [1,2,3]:
print 'Not Found'
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| msg51004 - (view) | Author: Guido van Rossum (gvanrossum) * |
Date: 2006-08-29 21:57 | |
Logged In: YES user_id=6380 Let me reject this as a waste of time right now. See my post "Premature optimization and all that" in the py3k list. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:56:19 | admin | set | github: 43903 |
| 2008-01-06 22:29:46 | admin | set | keywords:
- py3k versions: + Python 3.0 |
| 2006-08-28 17:38:19 | georg.brandl | create | |