How to Use If Else in One Line in Python: Simple Syntax & Examples

In Python, you can write an if else statement in one line using the ternary conditional operator: value_if_true if condition else value_if_false. This lets you choose between two values based on a condition in a single, concise expression.

Syntax

The one-line if else in Python uses this pattern:

• value_if_true: the result if the condition is true
• condition: the test that returns True or False
• value_if_false: the result if the condition is false

This expression returns value_if_true when condition is true, otherwise it returns value_if_false.

python

result = value_if_true if condition else value_if_false

Example

This example shows how to assign a message based on a number's value using one-line if else:

python

number = 10
message = "Even" if number % 2 == 0 else "Odd"
print(message)

Output

Even

Common Pitfalls

Common mistakes include:

• Forgetting the else part, which causes a syntax error.
• Using multiple statements instead of expressions, which is not allowed in one line.
• Confusing the order: the if comes after the true value, not before.

Here is a wrong and right example:

python

# Wrong (syntax error):
# result = if condition: value_if_true else: value_if_false

# Right:
condition = True
result = "Yes" if condition else "No"
print(result)

Output

Yes

Quick Reference

Part	Description	Example
value_if_true	Result if condition is true	"Even"
condition	Test that returns True or False	number % 2 == 0
value_if_false	Result if condition is false	"Odd"

Key Takeaways

Use the syntax: value_if_true if condition else value_if_false for one-line if else.

Always include the else part to avoid syntax errors.

The condition goes between the true and false values.

One-line if else is an expression, not a statement, so it returns a value.

Use it for simple conditional assignments or expressions to keep code concise.