How to Use If Else in Python: Simple Guide with Examples

In Python, use if to check a condition and run code only if it's true. Use else to run code when the condition is false. This helps your program make decisions and choose different actions.

Syntax

The if else statement lets your program choose between two paths based on a condition.

• if: checks a condition; if true, runs the indented code below.
• else: runs if the if condition is false.

python

if condition:
    # code runs if condition is True
else:
    # code runs if condition is False

Example

This example checks if a number is positive or not and prints a message accordingly.

python

number = 5
if number > 0:
    print("The number is positive.")
else:
    print("The number is zero or negative.")

Output

The number is positive.

Common Pitfalls

Common mistakes include forgetting the colon : after if or else, or not indenting the code inside the blocks properly. Also, using else without an if above causes errors.

python

wrong:
if number > 0
    print("Positive")
else
    print("Not positive")

correct:
if number > 0:
    print("Positive")
else:
    print("Not positive")

Quick Reference

Remember these tips when using if else in Python:

• Always end if and else lines with a colon :.
• Indent the code inside if and else blocks by 4 spaces.
• else runs only if the if condition is false.
• Use elif for multiple conditions (not covered here).

Key Takeaways

Use if to run code when a condition is true and else when it is false.

Always put a colon : after if and else lines.

Indent the code inside if and else blocks consistently.

For multiple choices, use elif (else if) statements.

Avoid syntax errors by checking colons and indentation carefully.