开发者

How to sum columns in list with text fields

Say I've a Pyt开发者_高级运维hon list as below:

list =  [ ['text',2,3,4], ['text2',4,5,6] ]
y= map(sum,zip(*list))
print y 

Gives int /str error.

How would I pop all 'text' in all rows and sum the remaining columns. Ans: Im looking for [6, 8, 10] I noticed that field look like int but are str. 4 vs '4'.


In [111]: lst =  [ ['text',2,3,4], ['text2',4,5,6] ]

In [112]: import operator

In [113]: print(map(operator.add,*lst))
['texttext2', 6, 8, 10]

If you don't know a priori which columns contain text, then you could use a try..except block to handle the text:

lst =  [ ['text',2,3,4], ['text2',4,5,6] ]
result=[]
for column in zip(*lst):
    try:
        result.append(sum(map(int,column)))
    except ValueError:
        pass
print(result)
# [6, 8, 10]


>>> map(sum, zip(*list)[1:])
[6, 8, 10]

>>> list =  [ ['text','2','3','4'], ['text2','4','5','6'] ]
>>> map(sum , [map(int,i) for i in zip(*list)[1:]] )
[6, 8, 10]
>>>


y = map(lambda x: sum(int(k) for k in x[1:]),
        zip(*list))

If you also expect decimals, you can change it to float() instead of int()


def tail(l):
    return l[1:]

map(sum, zip(*map(tail, list))

Note: I have been doing too much Haskell lately. ;-)

0

上一篇:

下一篇:

精彩评论

暂无评论...
验证码 换一张
取 消

最新问答

问答排行榜