问题描述
我正在尝试找到一种有效的方法来执行以下操作:
I'm trying to find an efficient way to do the following:
我有这个样本:
sample = [['no',2, 6], ['ja',5,7], ['no',4,9], ['ja',10,11], ['ap',7,12]]
并且需要
res = [['no', 6, 15], ['ja', 15, 18], ['ap',7,12]]
即将第一个元素相同的子列表的对应值相加.
i.e. sum the corresponding values of the sublists where the first element is the same.
非常感谢
我的代码是:
codes = list(set([element[0] for element in sample])) res=[] for code in codes: aux=[code] res01 = 0 res02 = 0 for element in sample: if element[0] == code: res01 += element[1] res02 += element[2] aux += [res01, res02] res.append(aux)
推荐答案
使用defaultdict:
>>> from collections import defaultdict >>> d = defaultdict(lambda: [0,0], list()) >>> for a,b,c in sample: d[a][0]+=b d[a][1]+=c
#driver 值:
IN : sample = [['no',2, 6], ['ja',5,7], ['no',4,9], ['ja',10,11], ['ap',7,12]] OUT : d = defaultdict(<function <lambda> at 0x7f4349f17620>, {'no': [6, 15], 'ja': [15, 18], 'ap': [7, 12]})
由于输出的结构是这样的,我建议您使用 dict 类型来存储您的输出,因为将来处理它会更容易.
Since the output is structured as such, I would suggest you utilise the dict type for storing your output as future processing with it will be easier.
如果您仍然希望输出为 list,只需映射 dict,如下所示:
In case you still want the output as a list, just map the dict, as follows:
>>> [ [key]+ele for key,ele in d.items()] => [['no', 6, 15], ['ja', 15, 18], ['ap', 7, 12]]