Category: Analytics
Missing data and dtypes
Nulls, empty strings, and bad dtypes break joins and totals in quiet ways. Learn safe pandas casting with coerce, careful fill versus drop, and a symptom-to-fix table you…
Joins and merges in plain English
Learn how pandas merges map to SQL joins, when row counts explode, and how to check keys with validate and indicator. A customers-and-orders walkthrough keeps grain honest before…
Aggregations and groupby
Learn pandas groupby as split-apply-combine, the same idea as SQL GROUP BY. Build sum, mean, count, and multi-metric aggregations, with a clear sales-by-region before and after table example.
Selecting, filtering, and sorting in pandas
Map SQL SELECT, WHERE, and ORDER BY onto clear pandas patterns you can debug at work. Select columns, filter with boolean masks, sort results, and keep method chains…
DataFrames as tables
A pandas DataFrame is just a table with rows, columns, and types you can inspect. Learn to load a CSV, check shape and dtypes, rename columns, and map…
