Python if, elif and else: Conditional Statements Explained

The if statement

An if statement runs a block of code only when a condition is true. The block is everything indented beneath the colon:

temperature = 31
if temperature > 30:
    print("It is hot today.")
    print("Drink water.")
print("This line always runs.")

Indentation is not decoration in Python — it is the syntax. Use four spaces (the app's editor inserts them automatically) and be consistent. Mixing tabs and spaces raises IndentationError.

else and elif

score = int(input("Score: "))
if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
elif score >= 70:
    grade = "C"
else:
    grade = "F"
print("Grade:", grade)

Python checks each condition from the top and runs the first block that is true, then skips the rest. Order matters: if you tested score >= 70 first, a score of 95 would get a C.

Combining conditions

age = 16
with_adult = True

if age >= 18 or (age >= 13 and with_adult):
    print("Admitted")
else:
    print("Not admitted")

username = ""
if not username:
    print("Username is required")

fruit = "kiwi"
if fruit in ("apple", "kiwi", "pear"):
    print("We stock that")

Nested if statements

logged_in = True
is_admin = False

if logged_in:
    if is_admin:
        print("Show admin panel")
    else:
        print("Show user dashboard")
else:
    print("Show login page")

Nesting works but gets hard to read past two levels. Often you can flatten it with and, or by returning early from a function (see functions).

The conditional expression (ternary)

n = 7
parity = "even" if n % 2 == 0 else "odd"
print(n, "is", parity)

items = 1
print(f"{items} item{'s' if items != 1 else ''}")

Use it for short, single-value choices. If either branch needs more than one expression, write a full if/else.

match statement (Python 3.10+)

For comparing one value against many patterns, match is cleaner than a long elif chain:

command = "stop"
match command:
    case "start" | "go":
        print("Starting")
    case "stop":
        print("Stopping")
    case _:
        print("Unknown command")

match can also destructure lists, tuples and dictionaries, which becomes useful once you work with structured data.

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Practice exercise

Write a program that asks for a year and prints whether it is a leap year. A year is a leap year if it is divisible by 4, except years divisible by 100, unless they are also divisible by 400.

year = int(input("Year: "))
if (year % 4 == 0 and year % 100 != 0) or year % 400 == 0:
    print(year, "is a leap year")
else:
    print(year, "is not a leap year")

The Coding Python app has a challenge like this that checks your answer automatically. Next up: loops.

Frequently asked questions