将两列相等长度的列合并为一列

Question

我有一个包含多个列的pandas DataFrame.我想要完成的是将两列的值组合/堆叠到一列中,将每列的值一行堆叠起来(不幸的是,此要求阻止我使用类似解的联合).其他剩余列的内容可以重复.非常感谢任何帮助

#Current DataFrame
print(df)
Stock Ticker    Index Ticker    Price   Date
AAPL            INDX            100     12/31/2018 8:57  
GOOG            RSL             123     12/31/2018 8:57
GM              COMP            90      12/31/2018 8:57
MMM             NIKK            340     12/31/2018 8:57
INVD            EUR             30      12/31/2018 8:57 

#Desired results
print(df2)
Stock and Bench   Price   Date
AAPL              100     12/31/2018 8:57
INDX              100     12/31/2018 8:57
GOOG              123     12/31/2018 8:57
RSL               123     12/31/2018 8:57
GM                90      12/31/2018 8:57
COMP              90      12/31/2018 8:57
MMM               340     12/31/2018 8:57
NIKK              340     12/31/2018 8:57
INVD              30      12/31/2018 8:57
EUR               30      12/31/2018 8:57

Answer 1

您可以将价格和日期列设置为索引并堆叠股票和股票代码.最后一些使用reset_index清理.

df.set_index(['Date', 'Price'])[['Stock Ticker','Index Ticker']].stack()\
.reset_index(2,drop = True).reset_index(name = 'Stock and Bench')


    Date    Price   Stock and Bench
0   12/31/2018 8:57 100 AAPL
1   12/31/2018 8:57 100 INDX
2   12/31/2018 8:57 123 GOOG
3   12/31/2018 8:57 123 RSL
4   12/31/2018 8:57 90  GM
5   12/31/2018 8:57 90  COMP
6   12/31/2018 8:57 340 MMM
7   12/31/2018 8:57 340 NIKK
8   12/31/2018 8:57 30  INVD
9   12/31/2018 8:57 30  EUR