Cheat sheets
The syntax you actually reach for — one dense, scannable page per tool.
Git Everyday Git plus the recovery commands — staging, branching, merging, rebasing, and undoing. NumPy Arrays, indexing, broadcasting, and vectorized math — the NumPy you actually use. Pandas Read, clean, reshape, group, and join data — the pandas operations you reach for every day. Python Core Python syntax, data structures, comprehensions, functions, and idioms — the essentials on one page. scikit-learn The estimator API, preprocessing, pipelines, model selection, and metrics — the sklearn workflow end to end. SQL SELECT to window functions — joins, aggregation, CTEs, and the query patterns analysts use daily.