if / elif / else

Run different code depending on a condition.

Syntaxif condition: ... elif other: ... else: ...

The if statement runs a block only when a condition is True. Add elif (else if) for more choices, and else for a fallback.

Structure

Each condition ends in a colon :, and the code to run is indented below it. Python checks each condition in order and runs the first that is True.

Example

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When to use it

  • A ticket booking app checks age with if/elif/else to apply child, adult, or senior pricing.
  • An authentication flow shows different pages based on whether a user is logged in.
  • A temperature monitor alerts operators with different severity messages depending on the reading.

More examples

Simple if/else

Runs the if branch because the condition is True, skipping the else block.

Example · python
balance = 250
if balance >= 100:
    print('Sufficient funds')
else:
    print('Insufficient funds')

# Output:
# Sufficient funds

if / elif / else chain

Uses elif to check multiple ranges in order and assigns the correct letter grade.

Example · python
score = 72
if score >= 90:
    grade = 'A'
elif score >= 80:
    grade = 'B'
elif score >= 70:
    grade = 'C'
else:
    grade = 'F'
print(grade)  # C

Nested if for combined conditions

Nests an inner if inside an outer if to apply a tiered discount based on membership and spend.

Example · python
is_member = True
cart_total = 120

if is_member:
    if cart_total >= 100:
        discount = 0.15
    else:
        discount = 0.05
else:
    discount = 0

print(f'Discount: {discount * 100:.0f}%')  # Discount: 15%

Related

py comparisonpy match

Discussion

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