python 添加两个列表并创建一个新列表

Question

lst1 = ['company1,AAA,7381.0 ', 'company1,BBB,-8333.0 ', 'company1,CCC,
3079.999 ', 'company1,DDD,5699.0 ', 'company1,EEE,1640.0 ',
       'company1,FFF,-600.0 ', 'company1,GGG,3822.0 ', 'company1,HHH,-600.0 ',
       'company1,JJJ,-4631.0 ', 'company1,KKK,-400.0 ']

lst2 =['company1,AAA,-4805.0 ', 'company1,ZZZ,-2576.0 ', 'company1,BBB,1674.0 ', 'company1,CCC,3600.0 ', 'company1,DDD,1743.998 ']

我需要的输出==

['company1,AAA,2576.0','company1,ZZZ,-2576.0 ','company1,KKK,-400.0 ' etc etc]

我需要在每个列表中添加类似的产品编号并将其移至新列表。我还需要将任何未添加到一起的符号添加到该新列表中。我在浏览每个列表时遇到问题。

这就是我所拥有的:

h = [] 

z = []         

a = []        

for g in lst1:
    spl1 = g.split(",")
    h.append(spl1[1])
for j in lst2:
    spl2 = j.split(",")
    **if spl2[1] in h:
        converted_num =(float(spl2[2]) +float(spl1[2]))
        pos=('{0},{1},{2}'.format(spl2[0],spl2[1],converted_num))
        z.append(pos)**
    else:
        pos=('{0},{1},{2}'.format(spl2[0],spl2[1],spl2[2]))
        z.append(pos)

for f in z:
    spl3 = f.split(",")
    a.append(spl3[1])

for n in lst1[:]:
    spl4 = n.split(",")
    if spl4[1] in a:
        got = (spl4[0],spl4[1],spl4[2])
        lst1.remove(n)
smash = lst1+z #for i in smash:
for i in smash:
    print(i)

我在迭代列表时遇到问题，以确保将所有类似产品添加到新列表(粗体)，并将不在列表 1 中但在 lst2 中的任何产品添加到新列表中，反之亦然。我确信有一种更简单的方法。

Answer 1

我赞同使用字典的建议。因为我很懒，所以我更喜欢使用 defaultdict 因为这样我就不必担心检查 key 是否存在。 (您也可以在此处使用 Counter。)特别是，假设您必须以列表开始和结束:

from collections import defaultdict

data = defaultdict(float)

for line in lst1+lst2:
    name, code, value = line.split(",")
    data[name, code] += float(value)

newlist = ['{},{},{}'.format(key[0], key[1], val) for key, val in sorted(data.items())]

给出

>>> data
defaultdict(<type 'float'>, {('company1', 'HHH'): -600.0, ('company1', 'JJJ'): -4631.0,
('company1', 'KKK'): -400.0, ('company1', 'DDD'): 7442.998, ('company1', 'ZZZ'): -2576.0,
('company1', 'CCC'): 6679.999, ('company1', 'AAA'): 2576.0, ('company1', 'FFF'): -600.0,
('company1', 'GGG'): 3822.0, ('company1', 'EEE'): 1640.0, ('company1', 'BBB'): -6659.0})

和

>>> newlist
['company1,AAA,2576.0', 'company1,BBB,-6659.0', 'company1,CCC,6679.999',
'company1,DDD,7442.998', 'company1,EEE,1640.0', 'company1,FFF,-600.0', 
'company1,GGG,3822.0', 'company1,HHH,-600.0', 'company1,JJJ,-4631.0', 
'company1,KKK,-400.0', 'company1,ZZZ,-2576.0']