Comments

Comments are notes you leave in your code for yourself and others. Python ignores them completely.

Single-line comments with

Anything after a # on a line is a comment:

python

### This is a comment
print("Hello")

### This comment sits at the end of a line

Multi-line comments

Python has no built-in multi-line comment. People use two tricks:

**Trick 1: a

on each line**

python

### This is line one

### This is line two

### This is line three

Trick 2: a multi-line string

python
"""
This is a multi-line string.

### Python ignores it when it's not assigned,
so it works like a comment.
"""

Why comment?

• Explain the "why", not just the "what". The code shows what; comments say why.
• Leave warnings about tricky parts.
• Temporarily disable a line while debugging.

Keep them useful

Too many comments are as bad as none. Write clear code, then use comments where they add real value.

TL;DR

• # starts a single-line comment.
• Use # on each line or a triple-quoted string for multi-line notes.
• Comments explain the "why" and are ignored by Python.