Python Syntax

Indentation

Python uses indentation (whitespace at the beginning of a line) to define code blocks. Other languages use curly braces. The standard is 4 spaces.

if True:
    print("Indented correctly")
# This would cause an error:
# if True:
# print("No indent")

Comments

Use # for single-line comments. Python has no built-in multi-line comment syntax, but you can use triple-quoted strings.

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

"""
This is a
multi-line string used
as a comment
"""

Try it yourself

Run the example below. Edit it and see what changes.

# Fix the indentation
if 5 > 2:
    print("Five is greater than two!")
 

Common mistakes

• ⚠Mixing tabs and spaces — pick one and stick with it (spaces preferred).
• ⚠Forgetting to indent after if, for, while, def, class, etc.