PD Scal się w wielu kolumnach
new_df = pd.merge(A_df, B_df, how='left', left_on=['A_c1','c2'], right_on = ['B_c1','c2'])
Hambo
new_df = pd.merge(A_df, B_df, how='left', left_on=['A_c1','c2'], right_on = ['B_c1','c2'])#suppose you have two dataframes df1 and df2, and
#you need to merge them along the column id
df_merge_col = pd.merge(df1, df2, on='id')m = {'left_only': 'df1', 'right_only': 'df2', 'both': 'df1, df2'}
result = df1.merge(df2, on=['A'], how='outer', indicator='B')
result['B'] = result['B'].map(m)
result