Pandas dataframe compare values == none / nothing / null

Question

I have 2 columns in the python dataframe. I want to check each row in my Column A for any value that is NOT == NaN. If the value is found then append the corresponding row with 'P' IF NaN value then 'B' In excel, I could use =if(A1="","B","P" assuming that a cell is empty and not NAN I think my excel background is confusing me as to what is considered empty or null vs what is the NaN value. <<Test Frame>> Column A | Column B 1 NaN NaN 2 John NaN 3 Dave NaN 4 NaN NaN 5 Michael NaN Output: <<Desired Output>> Column A | Column B 1 NaN B 2 John P 3 Dave P 4 NaN B 5 Michael P I have researched but couldn't find the fit for this particular purpose. Select the correct answer from above options

Answer 1

In python, we have np.where in numpy package import numpy as np df['colB'] = np.where(df['colA'].isna(), 'B', 'P') Learn data science with python course to improve your technical knowledge.