Chapter 4 of 12
Python conditionals use significant whitespace (indentation) instead of curly braces to define code blocks. This forced indentation is controversial but produces consistently readable code.
score = 78
if score >= 90:
print("A — Excellent")
elif score >= 75:
print("B — Good")
elif score >= 60:
print("C — Pass")
else:
print("F — Try again")
# Inline if (ternary equivalent)
grade = "pass" if score >= 60 else "fail"
# Multiple conditions
age = 25
has_id = True
is_member = False
if age >= 18 and has_id:
print("Entry allowed")
if is_member or age < 12:
print("Discounted price")
# Check for None
result = get_data()
if result is None:
print("No data returned")
if result is not None:
process(result)WARNING
Indentation is syntax — not style. Python uses indentation to define code blocks instead of curly braces. Consistent indentation (4 spaces is the standard) is not optional — inconsistent indentation causes IndentationError. Configure your editor to show whitespace and use 4-space indentation.