我如何擺脫python額外的數組？

Question

所以我的代碼如下：

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

我怎麼讓它去從那裏到這種狀態：

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

Answer 1

使用list comprehension：

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

與元組拆包：

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