Question library
Questions from real interviews. Drill any of them by voice in a couple of minutes, with an interviewer, a score and feedback.
How do you find and handle missing values in pandas?JuniorThere are two pandas DataFrames: orders with columns order_id, user_id, and amount, and users with columns user_id and country. Write a function revenue_by_country that takes both DataFrames and returns a DataFrame with the country, the number of unique buyers, and the total revenue, sorted by revenue in descending order.JuniorYou have a pandas script that processes a table of several million rows; it takes half an hour and sometimes runs out of memory. How would you speed it up?Mid-levelYou have a pandas script that processes a 20 GB CSV file, and it runs out of memory on a machine with 32 GB of RAM. What would you do?Senior