Practice / joins
Waveform wants a roster of every user next to their subscription plan — including the free-tier users who haven't picked a paid plan yet.
You have two DataFrames:
users
plans
Your task: return every user's handle and their plan_name. A user with no plan must still appear, with a null plan_name.
Assign your answer DataFrame to result. Row order doesn't matter.
usersinput DataFrame| column | type |
|---|---|
| user_id | long |
| handle | string |
| plan_id | long |
| user_id | handle | plan_id |
|---|---|---|
| 1 | ada | 10 |
| 2 | ben | 20 |
| 3 | cara | null |
plansinput DataFrame| column | type |
|---|---|
| plan_id | long |
| plan_name | string |
| plan_id | plan_name |
|---|---|
| 10 | Pro |
| 20 | Free |
handleplan_name· 3 rowsusers.join(plans, on="plan_id", how="left") keeps every user; those with no
plan get a null plan_name. Then select("handle", "plan_name").
This problem builds on Joins (~8 min). Pop it open in a new tab if you want a quick recap.