문제 설명
Python 2.x: 튜플 목록의 항목 합계 (Python 2.x: Summing items in a list of tuples)
요약을 위해 목록의 여러 항목이 동일한 첫 번째 변수를 갖는 튜플 목록을 만들었습니다. 예:
x = [('m32',[1,2,3]),('m32',[2,3,4]),('m32',[4,5,6]),('m33',[1,2,3]),('m33',[2,3,4]),('m33',[4,5,6]),('m34',[1,2,3]),('m34',[2,3,4]),('m34',[4,5,6])....]
튜플에 있는 두 번째 항목의 개별 값(예: 1+2+4, 2+3+5, 3+4+6)을 포함하는 모든 값에 대해 동일한 첫 번째 항목(예: 'm32').
즉, 'm32' 레이블이 지정된 모든 항목에 대해 다른 값을 추가할 수 있기를 원합니다.
어떻게 나는 이것을 슬라이스/인덱싱하여 반복하고 합계를 수행합니까?
참조 솔루션
방법 1:
Some tricky zip magic, along with itertools.groupby to group the matching first items together:
>>> x = [('m32',[1,2,3]),('m32',[2,3,4]),('m32',[4,5,6]),('m33',[1,2,3]),('m33',[2,3,4]),('m33',[4,5,6]),('m34',[1,2,3]),('m34',[2,3,4]),('m34',[4,5,6])]
>>> from itertools import groupby
>>> from operator import itemgetter
>>> for k,g in groupby(x,key=itemgetter(0)):
... print (k,[sum(i) for i in zip(*zip(*g)[1])])
...
('m32', [7, 10, 13])
('m33', [7, 10, 13])
('m34', [7, 10, 13])
A breakdown of how it works:
g is the group of items with matching keys. zip(*g) transposes the matrix, bringing the keys and values together:
>>> for k,g in groupby(x,key=itemgetter(0)):
... print zip(*g)
...
[('m32', 'm32', 'm32'), ([1, 2, 3], [2, 3, 4], [4, 5, 6])]
[('m33', 'm33', 'm33'), ([1, 2, 3], [2, 3, 4], [4, 5, 6])]
[('m34', 'm34', 'm34'), ([1, 2, 3], [2, 3, 4], [4, 5, 6])]
Getting the 2nd items:
>>> for k,g in groupby(x,key=itemgetter(0)):
... print zip(*g)[1]
...
([1, 2, 3], [2, 3, 4], [4, 5, 6])
([1, 2, 3], [2, 3, 4], [4, 5, 6])
([1, 2, 3], [2, 3, 4], [4, 5, 6])
Transposing again to match up the items to sum:
>>> for k,g in groupby(x,key=itemgetter(0)):
... print zip(*zip(*g)[1])
...
[(1, 2, 4), (2, 3, 5), (3, 4, 6)]
[(1, 2, 4), (2, 3, 5), (3, 4, 6)]
[(1, 2, 4), (2, 3, 5), (3, 4, 6)]
And adding them up:
>>> for k,g in groupby(x,key=itemgetter(0)):
... print [sum(i) for i in zip(*zip(*g)[1])]
...
[7, 10, 13]
[7, 10, 13]
[7, 10, 13]
방법 2:
The answer given by Mark is great, and probably much more efficient that the one I'll post you. But I still want to post my answer because you are probably new to python and it will be easy for you to understand it.
For this kind of scripts you only need some imagination and basic python notions:
dictionary={}
for name, numbers in x:
if name in dictionary:
current_list=dictionary[name]
for i in range(3):
current_list[i]+=numbers[i]
else:
dictionary[name]=numbers
print(dictionary)
Note that the output is a dictionary: {'m32': [7, 10, 13], 'm33': [7, 10, 13]}..
I hope it help you!
(by catalyst123、Mark Tolonen、user3672754)