So I know how to get the sum of a single list so say,
a=[1,2,3,4]
sum(a)
10
How would I go about trying to sum lists in a list of lists? So, from:
[[1,2],[2,3],[3,42]] to
[3,5,45]?
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Python programmer
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`[sum(lst) for lst in [[1,2],[2,3],[3,42]] ]` – Chris_Rands Jun 13 '19 at 12:19
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`print(list(map(sum, data)))` ? – Rakesh Jun 13 '19 at 12:19
3 Answers
2
Code:
l = [[1,2],[2,3],[3,42]]
print([sum(i) for i in l])
Output:
[3, 5, 45]
Olvin Roght
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You should use sum() in list comprehension for other lists
In [12]: a = [[1,2],[2,3],[3,42]]
In [13]: [sum(i) for i in a]
Out[13]: [3, 5, 45]
frankegoesdown
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intial_list = [[1,2],[2,3],[3,42]]
res = list(map(sum, intial_list))
print(res)
output
[3,5,45]
sahasrara62
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@OlvinRoght removed lambda , new one is faster than list comprehension – sahasrara62 Jun 13 '19 at 12:30
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@prashantrana, yes map is a bit faster then list comprehension on bigger data, just less obvious. – Olvin Roght Jun 13 '19 at 12:36
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1Your *text* still states that you're using lambda, which you're not! – paxdiablo Aug 10 '20 at 07:51