Interactive Python F-strings Lab

Learn Python F-strings Interactively

What are F-strings?

F-strings, or formatted string literals (introduced in Python 3.6), offer a concise way to embed Python expressions inside strings using an f prefix and curly braces {}.

How to Use This Interactive Demo

Below are two separate examples. Modify the input values in each section to see the corresponding F-string Syntax and Result update in real-time for that specific example.

Basic F-string: Variable Substitution

Inputs

Name:

Age:

City:

Example

Python F-string Syntax:

Result:

Explanation:

Explanation: The variables name, age, and city are directly embedded within the curly braces {} inside the f-string. Python replaces {name} with the current value of the name variable, and so on. This is the simplest use case for f-strings.

Advanced F-string: Formatting & Expressions

Inputs

Item:

Price ($):

Tax Rate (0-1):

Example

Python F-string Syntax:

Result:

Explanation:

Explanation:

Expressions: Any valid Python expression works inside {}, like item.upper() or calculations like price * (1 + tax).
Format Specifiers: Use a colon : for formatting (e.g., :.2f for 2 decimal places, :.1% for percentage).
Multi-line: Triple quotes f"""...""" handle multi-line strings.
Literal Braces: Use {{ or }} for literal curly braces.