two conditions multiplication in pandas

I have the following dataframe, and I am trying to get revenue column by a multiplication between columnA or columnB and columnC.

The condition is:

• if columnB is NaN, then the revenue column = columnA * columnC
• if columnB is not NaN, then the revenue column = columnB * columnC

type   columnA     columnB     columnC
1        23          NaN          2
2        14          35           3
3        11          NaN          4
4        29          12           5

how do I get this revenue column with these two condition in python? Thanks in advance.

Answer

First you can check if columnB contains any NaN values using .isnull().values.any() then apply an if else condition to get the desired revenue column.

Here’s how you can do it:

df['revenue'] = df['columnA'] * df['columnC'] if df['columnB'].isnull().values.any() else df['columnB'] * df['columnC']

Output:

   type  columnA  columnB  columnC  revenue
0     1       23      NaN        2       46
1     2       14     35.0        3       42
2     3       11      NaN        4       44
3     4       29     12.0        5      145