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17. Payment Method Imputation
easy
Applesenior
How would you replace null or missing payment_method values with "unknown" in appstore_transactions and return all columns ordered by user_id ascending and transaction_dt descending?
appstore_transactions
| Column Name | Type |
|---|---|
| transaction_id | int64 |
| user_id | int64 |
| app_name | object |
| transaction_dt | object |
| payment_method | object |
| price | float64 |
| device | object |
| rating | float64 |
Expected Output Schema
| Column Name | Type |
|---|---|
| transaction_id | int64 |
| user_id | int64 |
| app_name | object |
| transaction_dt | datetime64[ns] |
| payment_method | object |
| price | float64 |
| device | object |
| rating | float64 |
Constraints
Keep all columns in output
Sort: user_id asc, transaction_dt desc
Hint 1
Look for a SQL function that replaces NULLs in a single column with a constant string.
Hint 2
Use COALESCE(payment_method, 'unknown') to replace missing values.
Hint 3
After replacing nulls, sort with ORDER BY user_id ASC, transaction_dt DESC.
Roles
Data Scientist
Data Analyst
Data Engineer
Companies
AppleLevels
senior
entry
Tags
pandas
data-cleaning
missing-values
sorting
dataframe
30 people are solving this problem
Python EditorLn 1, Col 1