CODEWITHSUNDEEP
pythonpandasdataframe
Carl
Carl

Reputation: 1371

Multiplying two separate dataframes

I have two dataframes and I would like to use them to create a third by applying a simple function. The datasets are quite large so instead of looping through every row and column, is there a more efficient way to do this?

# dfA
id   | value |
mars | 10    |
jupt | 15    |
satn | 14    |


# dfB
id   | A   | B   | C   |
satn | 0.5 | 0.3 | 0.2 |
mars | 0.2 | 0.5 | 0.3 |
jupt | 0.6 | 0.3 | 0.1 |

End result should be a multiplication of dfA by the corresponding id in dfB

# dfResult
id   | A      | B      | C      |
mars | 10*0.2 | 10*0.5 | 10*0.3 |
jupt | 15*0.5 | 15*0.3 | 15*0.1 |
satn | 14*0.5 | 14*0.3 | 14*0.2 |

Upvotes: 1

Views: 49

Answers (1)

jezrael
jezrael

Reputation: 862406

Use DataFrame.set_index for match, multiple by DataFrame.mul and last create column from index:

df = dfB.set_index('id').mul(dfA.set_index('id')['value'], axis=0).reset_index()
print (df)
     id    A    B    C
0  jupt  9.0  4.5  1.5
1  mars  2.0  5.0  3.0
2  satn  7.0  4.2  2.8

Upvotes: 3

Related Questions