python panda：返回常见行的索引

不需要带有连接值的新列，默认情况下，通过两个列进行内部合并，如果需要，则使用

df2.index

reset_index

df1 = pd.Dataframe({'col1':['cx','cx','cx2'], 'col2':[1,4,12]})df2 = pd.Dataframe({'col1':['cx','cx','cx','cx','cx2','cx2'], 'col2':[1,3,5,10,12,12]})df3 = pd.merge(df1,df2.reset_index(), on = ['col1','col2'])print (df3)  col1 col2  index0   cx    1      01  cx2   12      42  cx2   12      5

对于两个索引都需要：

df4 = pd.merge(df1.reset_index(),df2.reset_index(), on = ['col1','col2'])print (df4)   index_x col1  col2  index_y0        0   cx     1        01        2  cx2    12        42        2  cx2    12        5

仅对于两个Dataframe的交集：

df5 = pd.merge(df1,df2, on = ['col1','col2'])#if 2 column Dataframe   #df5 = pd.merge(df1,df2)print (df5)  col1  col20   cx     11  cx2    122  cx2    12