用python连接列表

Question

在python中，将列表列表连接到单个列表（或迭代器）的语法是短的吗？

例如，我有一个列表，如下所示，我想遍历a、b和c

x = [["a","b"], ["c"]]

我能想到的最好的办法如下。

result = []
[ result.extend(el) for el in x] 

for el in result:
  print el

Answer 1

如果你只深入一个层次，嵌套式理解也会奏效：

>>> x = [["a","b"], ["c"]]
>>> [inner
...     for outer in x
...         for inner in outer]
['a', 'b', 'c']

在一条线上，它变成：

>>> [j for i in x for j in i]
['a', 'b', 'c']

Answer 2

x = [["a","b"], ["c"]]

result = sum(x, [])

Answer 3

import itertools
a = [['a','b'], ['c']]
print(list(itertools.chain.from_iterable(a)))