我如何在python中摆脱额外的数组？

Question

所以我的代码如下：

  promotion = [[""], ["promotion applied"],[""]]

如何让它从那里进入这种状态：

 promotion = ["", "promotion applied", ""]

Answer 1

使用list comprehension：

>>> promotion = [[""], ["promotion applied"],[""]]
>>> [x[0] for x in promotion]
['', 'promotion applied', '']

with tuple unpacking：

>>> [x for x, in promotion]  # works only if all items are single-item sequences.
['', 'promotion applied', '']