How to implement Lambda function when there is condition on diffrent cols?

Question

I have 3 cols in dataframe, [Rank, prev, original], i want to develop logic as : when prev==original, rank should be 1 else rank equals rank+1. please help me write this using apply lambda.

Thanks in advance

Answer 1

A better approach would be to use pandas Fancy indexing :

df[df['prev'] == df['original']]['Rank'] = 1
df[df['prev'] != df['original']]['Rank'] += 1