How to Format Output in Python: Syntax and Examples

In Python, you can format output using f-strings by placing expressions inside curly braces within a string prefixed with f. Alternatively, use the format() method or the older % operator for string formatting.

Syntax

Python offers several ways to format output strings:

• f-strings: Use f"text {variable}" to embed expressions directly.
• format() method: Use "text {}".format(value) to insert values.
• Percent (%) formatting: Use "text %s" % value (older style, less recommended).

Each method allows you to control how values appear in the output.

python

name = "Alice"
age = 30

# f-string
print(f"Name: {name}, Age: {age}")

# format() method
print("Name: {}, Age: {}".format(name, age))

# Percent formatting
print("Name: %s, Age: %d" % (name, age))

Output

Name: Alice, Age: 30
Name: Alice, Age: 30
Name: Alice, Age: 30

Example

This example shows how to format numbers with decimals and align text using f-strings.

python

price = 49.99
quantity = 5

# Format price with 2 decimals
print(f"Price: ${price:.2f}")

# Align quantity right in 3 spaces
print(f"Quantity: {quantity:>3}")

# Combine text and calculations
total = price * quantity
print(f"Total: ${total:.2f}")

Output

Price: $49.99
Quantity:   5
Total: $249.95

Common Pitfalls

Common mistakes when formatting output include:

• Using the old % formatting which is less readable and flexible.
• Forgetting to prefix strings with f when using f-strings, causing variables to print literally.
• Incorrect format specifiers causing errors or wrong output.

python

# Wrong: missing f prefix
name = "Bob"
print("Hello, {name}!")  # prints literally

# Right: with f prefix
print(f"Hello, {name}!")

Output

Hello, {name}!
Hello, Bob!

Quick Reference

Method	Syntax Example	Description
f-string	f"Name: {name}"	Embed expressions directly, modern and preferred
format()	"Name: {}".format(name)	Insert values using placeholders
Percent (%)	"Name: %s" % name	Older style, less flexible

Key Takeaways

Use f-strings for clear and concise output formatting in Python 3.6+.

The format() method is useful for older Python versions or complex formatting.

Avoid the old % formatting style for new code.

Always prefix strings with f when using f-strings to embed variables.

Use format specifiers to control number precision and text alignment.