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Python If/Else — Making Decisions in Code

Learn how Python makes choices using if, elif, and else — the building blocks of smart programs that react to different situations.

Programs That Think

Every day, you make tons of decisions: 'If it's raining, I'll take an umbrella. Otherwise, I'll wear sunglasses.' Your brain checks a condition (is it raining?) and does different things based on the answer. Python works the exact same way! With if/else statements, your code can check conditions and decide what to do. This is what makes programs smart — they don't just do the same thing every time, they react to different situations.

Your First If Statement

python

age = 12

if age >= 13:
    print("You can create a social media account!")
else:
    print("You're not old enough yet.")
    print(f"Wait {13 - age} more year(s)!")

# Output:
# You're not old enough yet.
# Wait 1 more year(s)!

How It Works

Here's the recipe: 1. if — checks a condition (is something true?) 2. The condition — a question that's either True or False (like age >= 13) 3. Colon : — always put this after the condition 4. Indented code — the lines underneath that are pushed right (4 spaces) ONLY run if the condition is True 5. else: — what happens if the condition is False The indentation (those 4 spaces) is super important in Python. It's how Python knows which code belongs inside the if and which code is outside it.

Multiple Conditions with elif

python

# elif = "else if" — check another condition
score = 75

if score >= 90:
    grade = "A — Amazing!"
elif score >= 80:
    grade = "B — Great job!"
elif score >= 70:
    grade = "C — Not bad!"
elif score >= 60:
    grade = "D — Keep trying!"
else:
    grade = "F — Let's study more!"

print(f"Score: {score} => {grade}")
# Score: 75 => C — Not bad!

Comparison Operators

python

# These are the tools you use to compare things:
x = 10
y = 20

print(x == y)   # False  (equal to?)
print(x != y)   # True   (not equal to?)
print(x > y)    # False  (greater than?)
print(x < y)    # True   (less than?)
print(x >= 10)  # True   (greater than or equal?)
print(x <= 5)   # False  (less than or equal?)

# Combine conditions with 'and' / 'or'
age = 12
has_ticket = True

if age >= 10 and has_ticket:
    print("You can ride the rollercoaster!")

if age < 5 or age > 65:
    print("You get a discount!")

Pro Tip

Common mistake: using = instead of ==. A single = means 'set this value' (assignment). A double == means 'check if these are equal' (comparison). So 'if score = 100' will crash, but 'if score == 100' works perfectly.

Try It Yourself

Build a ticket price calculator! Ask the user for their age using input(). If they're under 5, it's free. Ages 5-12 cost $8. Ages 13-17 cost $12. Adults 18-64 cost $15. Seniors 65+ cost $10. Print the price with a friendly message.

Python Variables & Data Types — Storing Information

Python Loops — Repeating Things Easily

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