Python Basics : If / Elif / Else

A simple guide to making decisions in Python using conditional statements.

What Are Conditional Statements?

Conditional statements allow Python to make decisions and run different code depending on whether a condition is True or False.

Python uses:

• if
• elif
• else

Basic Structure

if condition:
    # code runs if condition is True
elif another_condition:
    # code runs if the previous conditions are False AND this is True
else:
    # code runs if all conditions are False

Comparison Operators

Using input() With Numbers

input() returns a string, so we must convert it:

num = int(input("Enter a number: "))

Examples

1. Even or Odd

num = int(input("Enter a number: "))

if num % 2 == 0:
    print("Even number")
else:
    print("Odd number")

2. Check Age Group

age = int(input("Enter age: "))

if age < 13:
    print("Child")
elif age < 20:
    print("Teen")
elif age < 60:
    print("Adult")
else:
    print("Senior")

3. Positive, Negative, or Zero

num = int(input("Enter number: "))

if num > 0:
    print("Positive")
elif num < 0:
    print("Negative")
else:
    print("Zero")

Tips for Beginners

• Indentation (spaces) matters in Python.
• Every if, elif, and else ends with a :.
• Conditions must evaluate to True or False.
• Use int() when expecting a number.

What’s Next?

• loops (for, while)