连接单索引DataFrame：为了将单索引数据帧与多索引数据帧连接，该级别将匹配单索引帧的索引名称与多索引帧的级别名称索引帧。

# importing pandas module
import pandas as pd

# Define a dictionary containing employee data
data1 = {'Name':['Jai', 'Princi', 'Gaurav'],
'Age':[27, 24, 22]}

# Define a dictionary containing employee data
data2 = {'Address':['Allahabad', 'Kannuaj', 'Allahabad', 'Kanpur'],
'Qualification':['MCA', 'Phd', 'Bcom', 'B.hons']}

# Convert the dictionary into DataFrame 
df = pd.DataFrame(data1, index=pd.Index(['K0', 'K1', 'K2'], name='key'))

index = pd.MultiIndex.from_tuples([('K0', 'Y0'), ('K1', 'Y1'),
('K2', 'Y2'), ('K2', 'Y3')],
names=['key', 'Y'])

# Convert the dictionary into DataFrame 
df1 = pd.DataFrame(data2, index= index)


print(df, "\n\n", df1)