Pandas

Pandas is the Excel of Python. v3.0 (2025/2026) enforces Copy-on-Write (CoW), finally fixing the SettingWithCopyWarning confusion.

When to Use

• Data Cleaning: Loading CSV/Excel/SQL and cleaning it.
• Time Series: Unmatched datetime indexing capabilities.
• Small/Medium Data: Features that fit in RAM.

Core Concepts

DataFrame / Series

2D tables and 1D arrays.

Copy-on-Write (CoW)

Views are always views, copies are always copies. Modifying a view triggers a copy only if necessary.