Answers for "pandas merge on 2 columns"

merge two dataframes based on column

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

df_outer

pd merge on multiple columns

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

merge two dataframes based on column

df_merge_col = pd.merge(df_row, df3, on='id')

df_merge_col

merge two columns pandas

df["period"] = df["Year"] + df["quarter"]