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Control Flow

If, Elif, Else & match

Decisions in Python: if/elif/else, nested conditions, the conditional expression, and structural pattern matching with match/case.

3 min read5 runnable examples4-question quiz
Python
marks = int(input("Marks: "))
if marks >= 90:
    grade = "O"
elif marks >= 80:
    grade = "A+"
elif marks >= 70:
    grade = "A"
elif marks >= 60:
    grade = "B+"
elif marks >= 40:
    grade = "P"
else:
    grade = "F"
print("Grade:", grade)
Output
Marks: 73
Grade: A
Sample input is includedTry it Yourself

Key points:

  • A colon : ends the condition line; the block is the indented lines below.
  • elif (else-if) can repeat; else is optional and comes last.
  • Conditions can be any value — Python uses its truthiness.

Nested conditions and combining tests

Python
def leap_year(y):
    return (y % 4 == 0 and y % 100 != 0) or y % 400 == 0

for year in (1900, 2000, 2024, 2026):
    print(year, "leap" if leap_year(year) else "not leap")

age, has_id = 20, True
if age >= 18:
    if has_id:
        print("Entry allowed")
    else:
        print("Show an ID")
else:
    print("Too young")
Output
1900 not leap
2000 leap
2024 leap
2026 not leap
Entry allowed
Try it Yourself

The conditional expression

value_if_true if condition else value_if_false — Python's version of C's ?::

Python
n = 7
parity = "even" if n % 2 == 0 else "odd"
print(f"{n} is {parity}")
print(max(3, 9), min(3, 9))      # built-ins often replace simple ifs
Output
7 is odd
9 3
Try it Yourself

match / case (Python 3.10+)

match compares a value against patterns — like C's switch, but more powerful. There is no fall-through, so no break is needed.

Python
def describe(command):
    match command.split():
        case ["quit"] | ["exit"]:
            return "Goodbye"
        case ["go", direction]:
            return f"Moving {direction}"
        case ["add", x, y]:
            return f"{x} + {y} = {int(x) + int(y)}"
        case []:
            return "Say something"
        case _:                       # the wildcard: matches anything
            return f"Unknown command: {command}"

for cmd in ["go north", "add 4 5", "exit", "dance", ""]:
    print(repr(cmd), "->", describe(cmd))
Output
'go north' -> Moving north
'add 4 5' -> 4 + 5 = 9
'exit' -> Goodbye
'dance' -> Unknown command: dance
'' -> Say something
Try it Yourself

A simple value match looks just like a switch:

Python
def day_type(day):
    match day:
        case "Sat" | "Sun":
            return "weekend"
        case "Mon" | "Tue" | "Wed" | "Thu" | "Fri":
            return "weekday"
        case _:
            return "not a day"

print(day_type("Sun"), day_type("Wed"), day_type("Funday"))
Output
weekend weekday not a day
Try it Yourself

Test yourself

4 questions · pick an answer to check it instantly

  1. 1

    What is printed?

    Python
    x = 0
if x:
    print("A")
elif x == 0:
    print("B")
else:
    print("C")
  2. 2

    What is "pass" if 35 >= 40 else "fail"?

  3. 3

    In a match statement, what does case _: do?

  4. 4

    Does Python's match fall through to the next case like C's switch?

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