Usernames Chosen More Than Once
Problem
**DataFrame: `Signup`**
| Column | Type |
|-----------|---------|
| signup_id | int |
| username | varchar |
`signup_id` is unique. Each row is one signup attempt and the username that was entered.
Return a DataFrame with one column `Username` listing every `username` that appears **more than once**. Any order.
**Example** — if `maple` was entered twice and `cedar` once, only `maple` is returned.
Input data
Example rows — the live problem includes the full dataset.
| signup_id | username |
|---|---|
| 1 | maple |
| 2 | cedar |
| 3 | maple |
Expected output
Your answer should return 1 row with the columns Username.
Starter code (Pandas (Python))
import pandas as pd
def repeated_usernames(Signup) -> pd.DataFrame:
# Your code here
return SignupSolve this Pandas question free
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Solution & explanation
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