8. Combining Data
Chala mitrano, aaj aapan tables join karuya — concat (rows stack) aani merge (Excel XLOOKUP / Power BI relationship sarkha idea). Orders ⨝ Stores. UI re-teach nahi; concept + pandas syntax.
What you will learn in this chapter
- concat for stacking monthly files
- merge how='left' and how='inner'
- Validate join keys and row counts
- Relate mentally to XLOOKUP / relationships (no UI redo)
Fictional data
Blinkit / Amazon Now figures in this chapter are fictional sample data for learning only. They do not show real company numbers. People names are for practice; e-mails use example.com.
Concepts in this chapter
The chapter recap is at the end of the last concept page.