Python Academy · Lesson

f-string Expressions

Embed expressions in strings.

Lesson 1 of 413 steps

f-string Expressions is a free Python Academy lesson on CoddyKit. This is lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Python Academy learning path, and your progress syncs across the web and the CoddyKit app. The Python Academy course includes 4 lessons in total.

What is an f-string?

An f-string is a string prefixed with f that lets you embed Python expressions directly inside braces {}. Introduced in Python 3.6, they are the clearest way to build strings.

name = 'Ada'
print(f'Hello, {name}!')

Embedding variables

Any variable name placed in {} is replaced by its value, converted to a string automatically.

age = 30
city = 'Istanbul'
print(f'I am {age} and live in {city}.')

Inline arithmetic

You can put full expressions inside the braces, not just variable names. The expression is evaluated and its result inserted.

a = 6
b = 7
print(f'{a} times {b} is {a * b}')

Calling functions

Function and method calls work inside f-strings too, so you can transform values on the fly.

word = 'python'
print(f'Upper: {word.upper()}')
print(f'Length: {len(word)}')

Conditional expressions

A ternary expression fits neatly inside braces, letting you choose text based on a condition.

score = 72
print(f'You {"passed" if score >= 60 else "failed"} the exam.')

Accessing dict and list items

Indexing and key lookups work inside f-strings. Use a different quote style for string keys to avoid clashing with the outer quotes.

user = {'name': 'Lin', 'pts': 90}
nums = [10, 20, 30]
print(f"{user['name']} scored {user['pts']}")
print(f'First number: {nums[0]}')

Accessing attributes

You can reach into object attributes with dot notation right inside the braces.

import math
print(f'Pi is roughly {math.pi}')
print(f'E is roughly {math.e}')

The self-documenting equals sign

Add = after an expression to print both the expression text and its value. This is a great debugging shortcut introduced in Python 3.8.

x = 5
y = 12
print(f'{x + y = }')

Escaping braces

To include literal curly braces in the output, double them: {{ and }}.

value = 42
print(f'A set looks like {{{value}}}')

Multiline f-strings

Triple-quoted f-strings span multiple lines while still evaluating every embedded expression.

name = 'Sam'
role = 'admin'
report = f'''User: {name}
Role: {role}
Active: {True}'''
print(report)

Nesting f-strings

You can even nest expressions and call other f-string-producing code, building strings from smaller pieces.

items = ['a', 'b', 'c']
print(f'Items: {", ".join(items)}')

Quick Check

What will f'{2 + 3}' produce?

Answer it in the interactive lesson

Recap: f-string Expressions

You learned that f-strings:

Are prefixed with f and embed expressions in {}.
Evaluate arithmetic, function calls, indexing, attributes, and conditionals.
Support {expr = } for debugging output.
Use {{ and }} for literal braces and can span multiple lines.

name = 'World'
print(f'Hello {name}, 2+2={2+2}')

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Frequently Asked Questions

Is the “f-string Expressions” lesson free?

Yes — the full text of “f-string Expressions” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Python Academy course, upgrade to CoddyKit PRO. The Python Academy course includes 4 lessons in total.

What will I learn in “f-string Expressions”?

Embed expressions in strings. You practise Python Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Python Academy?

No prior experience is required. Python Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 1 of 4.

How long does the “f-string Expressions” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Python Academy lesson?

Yes. Every Python Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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