Learn Python, NumPy, and Pandas for Data Science
Start with an inspection pass
Check shape, column names, data types, missing values, and a few representative records. Verify what a row represents before calculating totals or averages.
Make cleaning decisions explicit
Missing values can mean different things; dropping them without analysis may bias the result. Check duplicates and category labels, document the rule used, and compare row counts before and after a transformation.
Use groupby for focused summaries
Pandas grouping can summarize records by time, category, or another meaningful field. Confirm the aggregation matches the question and include a denominator when comparing rates.
Keep notebooks readable
Use descriptive variable names, small functions for repeated steps, and markdown notes for assumptions. A notebook should make it clear how raw inputs became the reported result.