python - Calculate during merge using pandas -

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is there way perform calculations between columns while merging pandas dataframes? example, have following 2 dfs, , want multiply data corresponding ids:

df1 = dataframe({'id':['a','b','c'], 'data':[8,7,12]})  df2 = dataframe({'id':['b','a','c'], 'data':[3,2,1]})

the desired output be:

  id  data 0     16 1  b    21 2  c    12

i know possible merging, , multiplying so:

merged = pd.merge(df1, df2, how='left', on=['id']) merged['data'] = merged.data_x * merged.data_y merged[['id', 'data']]

however, large numbers of columns, quite cumbersome, since merged column names have _x , _y suffixes. pandas equivalent of following sql:

select a.id, a.data * b.data 'data' table left join table b  on a.id = b.id

in case, set index , multiply:

>>> df1 = pd.dataframe({'id':['a','b','c'], 'data':[8,7,12]}) >>> df2 = pd.dataframe({'id':['b','a','c'], 'data':[3,2,1]}) >>> df1.set_index("id") * df2.set_index("id")     data id           16 b     21 c     12

with reset_index if like:

>>> (df1.set_index("id") * df2.set_index("id")).reset_index()   id  data 0     16 1  b    21 2  c    12

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