Build fluency in pandas, NumPy, and Python data manipulation with problems covering groupby, merge, pivot tables, apply, string operations, and datetime handling. Every problem includes a built-in Python Visualizer that shows how your DataFrame transforms step-by-step — see how merge matches keys, how groupby collapses rows, and exactly where your logic diverges from the expected output. All problems run against real company-style datasets, graded instantly in your browser.
809 Python problems across 15 datasets