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Python If…Else

Q: What is elif in Python?

elif means "else if". It adds another condition to an if statement and is checked only when all the conditions above it were false.

Q: Does Python have a switch statement?

Python 3.10 added match / case, which covers switch-style logic and much more. See [Match Case](lesson:match).

Q: How do I write an if else in one line in Python?

Use a conditional expression: result = "pass" if score >= 50 else "fail".

Q: Can I have an if without an else?

Yes. else is optional. Without it, nothing happens when the condition is false.

BeginnerLesson 13 of 4711 min read10 runnable examples

Programs need to make decisions: grant access or not, pass or fail, discount or full price. Python makes these decisions with if, elif and else.

In this lesson

Run code only when a condition is true
Choose between branches with elif and else
Nest conditions and combine them
Write one-line conditional expressions

The if statement

if runs its indented block only when the condition is true.

Python

temperature = 38 if temperature > 37.5:    print("Fever detected")    print("Please see a doctor")print("Check complete")

Output

Fever detected
Please see a doctor
Check complete

The condition can be any expression. Python treats it as true or false using the truthiness rules from Operators & Booleans.

if … else

else runs when the condition is false. Exactly one of the two blocks runs.

Python

age = 16 if age >= 18:    print("You can vote")else:    print(f"You can vote in {18 - age} years")

Output

You can vote in 2 years

if … elif … else

elif (short for “else if”) checks another condition. Python tests the conditions from top to bottom and runs only the first block whose condition is true.

Python

marks = 74 if marks >= 90:    grade = "A"elif marks >= 75:    grade = "B"elif marks >= 60:    grade = "C"else:    grade = "F" print("Grade:", grade)

Output

Grade: C

Watch out

Order matters. If you test marks >= 60 first, a score of 95 would get “C”, because the first true branch wins and the rest are skipped.

Nested if

An if can sit inside another if. Each level adds 4 spaces of indentation.

Python

username = "admin"password = "s3cret" if username == "admin":    if password == "s3cret":        print("Welcome, admin")    else:        print("Wrong password")else:    print("Unknown user")

Output

Welcome, admin

Deep nesting is hard to read. Often you can flatten it with and:

Python

username, password = "admin", "s3cret" if username == "admin" and password == "s3cret":    print("Welcome, admin")else:    print("Login failed")

Output

Welcome, admin

Combine conditions

Python

day = "Saturday"is_holiday = Falsehour = 22 if day in ("Saturday", "Sunday") or is_holiday:    print("Weekend rates apply") if not is_holiday and 9 <= hour <= 18:    print("Office is open")else:    print("Office is closed")

Output

Weekend rates apply
Office is closed

Conditional expression (one-line if)

For a simple choice between two values, write the condition inline:

Python

stock = 0status = "In stock" if stock > 0 else "Sold out"print(status) n = 7print("even" if n % 2 == 0 else "odd")

Output

Sold out
odd

Empty blocks with pass

A block cannot be empty. Use pass as a placeholder while you are still writing the code:

Python

feature_ready = False if feature_ready:    pass          # TODO: call the new featureelse:    print("Using the old feature")

Output

Using the old feature

Common mistakes

Using = instead of == in a condition is a syntax error:

Python

x = 5if x = 5:    print("five")

Output

  File "main.py", line 2
    if x = 5:
       ^^^^^
SyntaxError: invalid syntax. Maybe you meant '==' or ':=' instead of '='?

x == 1 or 2 does not check whether x is 1 or 2. It means (x == 1) or 2, and 2 is always truthy:

Python

x = 7print(bool(x == 1 or 2))       # always True: a bugprint(x == 1 or x == 2)        # correctprint(x in (1, 2))             # correct and shorter

Output

True
False
False

Check your understanding

Predict the output

n = 15if n % 3 == 0:    print("Fizz")elif n % 5 == 0:    print("Buzz")else:    print(n)

Quick quiz

1. How many branches of an if/elif/else chain run?

Python runs the first true branch (or else) and skips the rest.

2. What does "yes" if 0 else "no" evaluate to?

0 is falsy, so the else value is used.

3. Which correctly tests whether x is 1 or 2?

x == 1 or 2 is always truthy, and (1 or 2) is just 1.

Exercise: shipping cost

Orders of 500 or more ship free. Otherwise shipping is 40, or 80 for express. Print the shipping cost for each order.

Input

(650, False), (300, False), (300, True)

Expected output

Order 650: shipping 0
Order 300: shipping 40
Order 300: shipping 80

Hint 1

Check the free-shipping rule first.

Python

orders = [(650, False), (300, False), (300, True)] for amount, express in orders:    if amount >= 500:        shipping = 0    elif express:        shipping = 80    else:        shipping = 40    print(f"Order {amount}: shipping {shipping}")

Output

Order 650: shipping 0
Order 300: shipping 40
Order 300: shipping 80

The free-shipping rule is tested first because it applies whether or not the order is express. The for line unpacks each tuple into amount and express.

Program Practice

64 Python If-Else Programs

Every program has a step-by-step explanation, colour-coded code and its real output.

Start practising →

#1EasyCheck if a number is divisible by 3 #2EasyNumbers from 1 to 30 divisible by 3 #3EasyAssign grades from marks #4EasyCheck divisibility by 3 and 5 #5EasySquare a number divisible by 11 #6MediumCheck a prime number

Related sets:All practice sets

Python if else FAQ

What is elif in Python?

elif means “else if”. It adds another condition to an if statement and is checked only when all the conditions above it were false.

Does Python have a switch statement?

Python 3.10 added match / case, which covers switch-style logic and much more. See Match Case.

How do I write an if else in one line in Python?

Use a conditional expression: result = "pass" if score >= 50 else "fail".

Can I have an if without an else?

Yes. else is optional. Without it, nothing happens when the condition is false.