棧上面列在大熊貓透視表中值標籤

Question

給出一個數據幀，看起來像：

import numpy as np 
import pandas as pd 

df = pd.DataFrame({ 
       'Key1': ['one', 'one', 'two', 'three'] * 3, 
       'Key2': ['A', 'B', 'C'] * 4, 
       'Value1': np.random.randn(12), 
       'Value2': np.random.randn(12) 
       }) 
print df 

 
    Key1 Key2 Value1 Value2 
0  one A 1.405817 1.307511 
1  one B -0.037627 -0.215800 
2  two C -0.116591 -1.195066 
3 three A 2.044775 -1.207433 
4  one B -1.109636 0.031521 
5  one C -1.529597 1.761366 
6  two A -1.349865 0.321454 
7 three B 0.814374 2.285579 
8  one C 0.178702 0.479210 
9  one A 0.718921 0.504311 
10 two B -0.375898 -0.379315 
11 three C -0.822250 0.703811 

我可以轉動它，這樣我得到的第一個鍵爲行和第二鍵列

pt = df.pivot_table(
    index=['Key1'], 
    columns=['Key2'], 
    values=['Value1','Value2'] 
    ) 

print pt 

 
     Value1      Value2      
Key2   A   B   C   A   B   C 
Key1                
one -0.076303 -0.899175 0.631831 -1.196249 0.339583 0.583173 
three 0.105773 0.460911 -0.387941 0.697660 1.091828 1.447365 
two 1.391854 0.499841 -0.422887 -0.366169 -0.230001 2.417211 

如何翻轉，使得值和列由列堆疊的第一和隨後的值，例如我看過MultiIndexes但我看不出這會如何影響佈局。

Answer 1

您可以使用MultiIndex.swaplevel和sort_index：

pt.columns = pt.columns.swaplevel(0,1) 
pt = pt.sort_index(axis=1) 
#pt = pt.sort_index(axis=1, level=0) 
print (pt) 
Key2   A     B     C   
     Value1 Value2 Value1 Value2 Value1 Value2 
Key1                
one 0.439076 -0.492287 -0.841044 0.435300 -0.490016 0.045178 
three -0.975650 0.276097 0.617394 -0.553229 0.213254 -0.044848 
two 0.291563 2.730831 -2.405110 -0.878826 -0.801219 0.908600 

與DataFrame.swaplevel另一種解決方案：

pt = pt.swaplevel(0,1, axis=1).sort_index(axis=1) 
print (pt) 
Key2   A     B     C   
     Value1 Value2 Value1 Value2 Value1 Value2 
Key1                
one 0.439076 -0.492287 -0.841044 0.435300 -0.490016 0.045178 
three -0.975650 0.276097 0.617394 -0.553229 0.213254 -0.044848 
two 0.291563 2.730831 -2.405110 -0.878826 -0.801219 0.908600