How to apply a function to a column given values from other columns?

Question

I have the function and want to create a new column df['growth_factor'] which will have a derived value in it. The tricky part is that two other columns need to be passed in a function for every row. import pandas as pd df = pd.DataFrame({"city":["losangeles", "losangeles", "newyork"], "beds":[3, 4, 4]}) def growth_factor(city,beds): if beds==3: if city == 'losangeles' : return 45 else: False elif beds==4: if city == 'losangeles' : return 47 elif city == 'newyork' : return 50 else: False else: False The function should pass into a df and should look like this: df= 'city' | 'beds' | 'growth_factor' losangeles |3 | 45 losangeles |4 | 47 newyork |4 | 50 How can I achieve this? Select the correct answer from above options

Answer 1

Use np.select: import numpy as np choices=[45,47,50] conditions=[(df['beds'].eq(3) & df['city'].eq('losangeles')), (df['beds'].eq(4) & df['city'].eq('losangeles')), (df['beds'].eq(4) & df['city'].eq('newyork'))] df['growth_factor']=np.select(conditions, choices, default='False') Output: df city beds growth_factor 0 losangeles 3 45 1 losangeles 4 47 2 newyork 3 False If you are a beginner and want to know more about Data Science the do check out the Data Science course