Python/Pandas - If Column A equals X or Y, then assign value from Col B. If not, then assign Col C. How to write in Python?

user_17380401 0
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I'm having trouble formulating this statement in Pandas that would be very simple in excel. I have a dataframe sample as follows:

    colA        colB                colC

10  0           27:15               John Doe
11  0           24:33               John Doe
12  1           29:43               John Doe
13  Inactive    John Doe            None
14  N/A         John Doe            None

Obviously the dataframe is much larger than this, with 10,000+ rows, so I'm trying to find an easier way to do this. I want to create a column that checks if colA is equal to 0 or 1. If so, then equals colC. If not, then equals colC. In excel, I would simply create a new column (new_col) and write

=IF(OR(A2<>0,A2<>1),B2,C2)

And then drag fill the entire sheet.

I'm sure this is fairly simple but I cannot for the life of me figure this out.

Result should look like this

    colA        colB                colC        new_col

10  0           27:15               John Doe    John Doe
11  0           24:33               John Doe    John Doe 
12  1           29:43               John Doe    John Doe
13  Inactive    John Doe            None        John Doe
14  N/A         John Doe            None        John Doe
pandas dataframe python
2 Answers

np.where should do the trick.

df['new_col'] = np.where(df['colA'].isin([0, 1]), df['colB'], df['colC'])
user_32824360

Here is a solution that adds your results to a list given your conditions, then adds the list back in the dataframe as D column.

your_results=[]
for i,data in enumerate(df["colA"]):
    if data==0 or data==1:
        your_results.append(df["colC"][i])
    else:
        your_results.append(df["colB"][i])
df["colD"]=your_results
user_146572080
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