if statement

Updated March 16, 2026 · Keywords

keyword conditional control-flow boolean

The if keyword is Python’s primary conditional statement. It executes code only when a specified condition evaluates to True.

Syntax

if condition:
    # Code runs when condition is True

You can add elif and else branches:

if condition1:
    # Runs if condition1 is True
elif condition2:
    # Runs if condition1 is False and condition2 is True
else:
    # Runs if both conditions are False

Basic Examples

Simple Condition

x = 10

if x > 5:
    print("x is greater than 5")
# x is greater than 5

With else

x = 3

if x > 5:
    print("x is greater than 5")
else:
    print("x is 5 or less")
# x is 5 or less

With elif

score = 75

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
elif score >= 70:
    grade = "C"
elif score >= 60:
    grade = "D"
else:
    grade = "F"

print(f"Grade: {grade}")
# Grade: C

Conditions and Boolean Values

Truthy and Falsy Values

Python treats certain values as False (falsy):

None
False
Zero: 0, 0.0, 0j
Empty sequences: "", [], ()
Empty dicts: {}
Objects with __bool__() returning False or __len__() returning 0

Everything else is truthy:

if "hello":
    print("String is truthy")
# String is truthy

if [1, 2, 3]:
    print("Non-empty list is truthy")
# Non-empty list is truthy

if 42:
    print("Non-zero number is truthy")
# Non-zero number is truthy

Comparison Operators

x = 5
y = 10

if x < y:
    print("x is less than y")
# x is less than y

if x == 5:
    print("x equals 5")
# x equals 5

if x != 0:
    print("x is not zero")
# x is not zero

Logical Operators

Combine conditions with and, or, not:

age = 25
has_license = True

if age >= 18 and has_license:
    print("Can drive")
# Can drive

if age < 18 or not has_license:
    print("Cannot drive")

Ternary Conditional Expression

One-line conditional expression:

age = 20
status = "adult" if age >= 18 else "minor"
print(status)
# adult

Nested Conditionals

x = 10

if x > 0:
    if x > 5:
        print("x is positive and greater than 5")
    else:
        print("x is positive but 5 or less")
else:
    print("x is not positive")
# x is positive and greater than 5

Common Patterns

Checking None

value = None

if value is None:
    print("No value provided")
# No value provided

value = "hello"
if value is not None:
    print(f"Value is: {value}")
# Value is: hello

Empty Collection Check

my_list = []

if my_list:
    print("List has items")
else:
    print("List is empty")
# List is empty

Multiple Conditions

user_role = "admin"
access_level = 3

if user_role == "admin" and access_level >= 2:
    print("Full access granted")
# Full access granted

Best Practices

Avoid Redundant Comparisons

# Avoid
if is_valid == True:

# Prefer
if is_valid:

Use elif Instead of Nested if

# Avoid
if x > 10:
    print("A")
else:
    if x > 5:
        print("B")
    else:
        print("C")

# Prefer
if x > 10:
    print("A")
elif x > 5:
    print("B")
else:
    print("C")

Keep Conditions Simple

Extract complex conditions into descriptive variables:

# Less readable
if user.is_active and user.has_subscription and user.subscription.is_valid:
    print("Can access")

# More readable
can_access = (
    user.is_active 
    and user.has_subscription 
    and user.subscription.is_valid
)

if can_access:
    print("Can access")