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Groups > comp.lang.python > #35790
| From | Terry Reedy <tjreedy@udel.edu> |
|---|---|
| Subject | Re: dict comprehension question. |
| Date | 2012-12-29 18:22 -0500 |
| References | <724d4fea-606a-4503-b538-87442f6bcebc@ci3g2000vbb.googlegroups.com> <50DF4C00.2020505@lightbird.net> <50DF4E15.1030700@lightbird.net> <CAPM-O+w8aYZ2zJcmc+ZyHOHmA7yt8OYPYAqhGWSB5tQgbnqRdA@mail.gmail.com> <50DF6334.7050600@lightbird.net> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.1453.1356823379.29569.python-list@python.org> (permalink) |
On 12/29/2012 4:40 PM, Mitya Sirenef wrote:
> On 12/29/2012 03:15 PM, Joel Goldstick wrote:
>> Would this help:
>>
>> >>> w = [1,2,3,1,2,4,4,5,6,1]
>> >>> s = set(w)
>> >>> s
>> set([1, 2, 3, 4, 5, 6])
>> >>> {x:w.count(x) for x in s}
>> {1: 3, 2: 2, 3: 1, 4: 2, 5: 1, 6: 1}
>> >>>
>
>
> Indeed, this is much better -- I didn't think of it..
It still turns an O(n) problem into an O(k*n) problem, where k is the
number of distinct items.
--
Terry Jan Reedy
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dict comprehension question. Quint Rankid <qbr567@gmail.com> - 2012-12-29 11:48 -0800
Re: dict comprehension question. Roy Smith <roy@panix.com> - 2012-12-29 14:58 -0500
Re: dict comprehension question. Mitya Sirenef <msirenef@lightbird.net> - 2012-12-29 15:01 -0500
Re: dict comprehension question. Mitya Sirenef <msirenef@lightbird.net> - 2012-12-29 15:09 -0500
Re: dict comprehension question. Joel Goldstick <joel.goldstick@gmail.com> - 2012-12-29 15:15 -0500
Re: dict comprehension question. Peter Otten <__peter__@web.de> - 2012-12-29 21:32 +0100
Re: dict comprehension question. MRAB <python@mrabarnett.plus.com> - 2012-12-29 20:39 +0000
Re: dict comprehension question. Mitya Sirenef <msirenef@lightbird.net> - 2012-12-29 16:40 -0500
Re: dict comprehension question. Terry Reedy <tjreedy@udel.edu> - 2012-12-29 18:22 -0500
Re: dict comprehension question. Terry Reedy <tjreedy@udel.edu> - 2012-12-29 18:56 -0500
Re: dict comprehension question. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-01-01 03:10 +0000
Re: dict comprehension question. 88888 Dihedral <dihedral88888@googlemail.com> - 2013-01-01 00:40 -0800
Re: dict comprehension question. Tim Chase <python.list@tim.thechases.com> - 2012-12-29 18:26 -0600
Re: dict comprehension question. Joel Goldstick <joel.goldstick@gmail.com> - 2012-12-29 23:10 -0500
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