merge dataframe pandas

1pd.merge(df1, df2, left_index=True, right_index=True)
2

1df_outer = pd.merge(df1, df2, on='id', how='outer') #here id is common column
2
3df_outer
4

1new_df = pd.merge(A_df, B_df,  how='left', left_on=['A_c1','c2'], right_on = ['B_c1','c2'])

1df.merge(df2, left_on = "doc_id", right_on = "doc_num", how = "left")

1# df1 as main df and use the feild from df2 and map it into df1
2
3df1.merge(df2,on='columnName',how='left')

1>>> df1.merge(df2, left_on='lkey', right_on='rkey')
2  lkey  value_x rkey  value_y
30  foo        1  foo        5
41  foo        1  foo        8
52  foo        5  foo        5
63  foo        5  foo        8
74  bar        2  bar        6
85  baz        3  baz        7
9