Pro exercise
Keep the first row, not the first values
Keep each person's earliest sign-up row, whole. pandas groupby().first() takes the first non-missing value of each column separately, stitching together a record that never existed. If the earliest row has no phone, the result has no phone.
- pandas
- duplicates
- survivor rules
Sign in with a Pro or Lifetime plan to open the rules, the dataset and the workspace.