Naming Rules

INTERACTIVE CHEAT SHEET

The Concept

Python variable names must start with a letter or underscore, and can only contain letters, digits, and underscores. Names are case-sensitive, so "score" and "Score" are different variables. You cannot use Python reserved keywords like class, if, or return as variable names.

Key Points

Must start with a letter (a–z, A–Z) or underscore (_).
Can contain letters, digits (0–9), and underscores only.
Names are case-sensitive: score ≠ Score ≠ SCORE.
Cannot use Python keywords like class, if, for, return.

Core Concept Mastery • Python Visual Series Module