Python中stack()的用法

先看例子

print(df2)
stacked = df2.stack()
stacked

输出
                     A         B
first second                    
bar   one     1.600260 -1.658585
      two    -0.594049  0.370097
baz   one    -0.512893 -1.428031
      two    -0.940714 -0.105024
first  second   
bar    one     A    1.600260
               B   -1.658585
       two     A   -0.594049
               B    0.370097
baz    one     A   -0.512893
               B   -1.428031
       two     A   -0.940714
               B   -0.105024
dtype: float64

可以看出，对于有经济学实证研究经历的朋友很易于理解这个函数，即将宽数据转变为长数据，逆操作则为unstack()