如何根据数据框中另一列的值将数据输入到新列中？

Question

I have a very large data frame with campaign finance data - the data frame has a column for the candidate's committee name, but not one for the candidates name.

How can I add a new column for the candidates name automatically based on the committee name? I want the code to read the committee name in each row, and then assign the appropriate candidate name.

Answer 1

Assuming there is a one to one mapping between committee name and candidate name, which you can describe in a dictionary, you would just need to use the map function.

Example Code:

>>> import pandas as pd
>>> data  = pd.DataFrame([["A"], ["B"], ["A"], ["C"]], columns=["Committee Name"])
>>> data
  Committee Name
0              A
1              B
2              A
3              C
>>> committee_name_mapping = {"A": "AName", "B": "BName", "C": "CName"}
>>> data["Candidate Name"] = data["Committee Name"].map(committee_name_mapping)
>>> data
  Committee Name Candidate Name
0              A          AName
1              B          BName
2              A          AName
3              C          CName