dict comprehension question.
Terry Reedy
tjreedy at udel.edu
Sat Dec 29 18:22:20 EST 2012
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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