python - 如何在单行中使用 for 循环将这些列表拆分为列表？

Question

我想把 pandas 中的 list flatten([[list1], [list2], [list3] ....])

有人能告诉我如何在单行中制作“for 循环”吗？谢谢(还有其他办法解决吗？)

words = []
for sent in train['tokenize']:
    words += sent

我想要的结果是 [[list1], [list2], [list3]] >> [list1, list2, list3]

Answer 1

使用列表理解:

words = [a for sub in train['tokenize'] for a in sub]

或chain.from_iterable :

from  itertools import chain
words = list(chain.from_iterable(train['tokenize']))

示例:

train = pd.DataFrame({'tokenize':[['a','s','d'],['ss','dd'],['aa','ss','dd']]})
print (train)
       tokenize
0     [a, s, d]
1      [ss, dd]
2  [aa, ss, dd]

words = [a for sub in train['tokenize'] for a in sub]
print (words)
['a', 's', 'd', 'ss', 'dd', 'aa', 'ss', 'dd']