代码＃2：DataFrames Merge

Pandas提供单个函数merge（），作为DataFrame对象之间所有标准数据库连接操作的入口点。

# Python program to merge

# dataframes using Panda

# Dataframe created

left = pd.DataFrame({'Key': ['K0', 'K1', 'K2', 'K3'],

'A': ['A0', 'A1', 'A2', 'A3'],

'B': ['B0', 'B1', 'B2', 'B3']})

right = pd.DataFrame({'Key': ['K0', 'K1', 'K2', 'K3'],

'C': ['C0', 'C1', 'C2', 'C3'],

'D': ['D0', 'D1', 'D2', 'D3']})

# Merging the dataframes

pd.merge(left, right, how ='inner', on ='Key')

# Python program to join

# dataframes using Panda

left = pd.DataFrame({'A': ['A0', 'A1', 'A2', 'A3'],

'B': ['B0', 'B1', 'B2', 'B3']},

index = ['K0', 'K1', 'K2', 'K3'])

right = pd.DataFrame({'C': ['C0', 'C1', 'C2', 'C3'],

'D': ['D0', 'D1', 'D2', 'D3']},

index = ['K0', 'K1', 'K2', 'K3'])

# Joining the dataframes

left.join(right)