Python interview questions

10 questions with answers, grouped by topic.

Python basics for data

Just enough language to be productive with data.

1

Why avoid looping over DataFrame rows?beginner

Working with DataFrames

Loading, inspecting, selecting and filtering.

3

What is the difference between loc and iloc?beginner What causes SettingWithCopyWarning?intermediate What is the difference between apply, map and applymap?intermediate

Wrangling & cleaning

Missing values, duplicates, text and types.

2

How do you handle missing values in pandas?beginner How do you find and remove duplicate records?beginner

Aggregation & reshaping

groupby, sorting, merging and pivoting.

4

What is the difference between merge and concat?intermediate When would you use groupby().transform() instead of agg()?intermediate How would you reshape wide data into long?intermediate How do you check that a merge worked correctly?intermediate