垂直复制熊猫数据帧

Question

我有这个foll。据帧：

Month Day season 
0  4 15 current 
1  4 16 current 
2  4 17 current 
3  4 18 current 
4  4 19 current 
5  4 20 current 

我想复制它，像这样：

Month Day season 
0  4 15 current 
1  4 16 current 
2  4 17 current 
3  4 18 current 
4  4 19 current 
5  4 20 current 
6  4 15 past 
7  4 16 past 
8  4 17 past 
9  4 18 past 
10  4 19 past 
11  4 20 past 

我可以用它复制：

df.append([df]*2,ignore_index=True) 

但是，我怎么复制，使得season列有past作为重复值而不是current

Answer 1

我认为这将是assign的好例子，因为它允许你保持你的函数式编程风格（我赞同！）

In [144]: df.append([df.assign(season='past')]*2,ignore_index=True) 
Out[144]: 
    Month Day season 
0  4 15 current 
1  4 16 current 
2  4 17 current 
3  4 18 current 
4  4 19 current 
5  4 20 current 
6  4 15  past 
7  4 16  past 
8  4 17  past 
9  4 18  past 
10  4 19  past 
11  4 20  past 
12  4 15  past 
13  4 16  past 
14  4 17  past 
15  4 18  past 
16  4 19  past 
17  4 20  past