Code Without Fear

About the book

A program is a list of instructions, written so exactly that a machine can follow them without asking questions. That's it. There is no secret math, no genius required.

Programming feels hard mostly because of strange words and the fear of breaking something. This book removes both. Every new term is explained the first time it appears, every example is short enough to type by hand, and every chapter ends with a small exercise you can check against the answers at the back.

By the last chapter you'll have written a tip calculator, a to-do list, a temperature converter, a word counter and a complete number-guessing game, and you'll understand why each line is there. Every program was run in Python 3.13 before publication, and the output printed in the book is the output you'll see.

What you'll be able to do

• Install Python and run your first line in under ten minutes
• Store, change and print values with variables
• Make decisions with if/else and repeat work with loops
• Organize data with lists and dictionaries
• Read an error message calmly and fix what it points to

What's inside

1. —Before you start
2. 01Say hello to Python
3. 02Boxes with names: values and variables
4. 03Ask a question, use the answer
5. 04Let the program decide
6. 05Do it again: loops
7. 06Lists: many things in one place
8. 07Functions: name your own commands
9. 08Dictionaries: look things up
10. 09Errors are messages, not insults
11. 10Build a whole program
12. ACheat sheet
13. BAnswers to the Try It exercises

A taste of the book

# From 3.4, the tip calculator
bill = float(input("Bill amount: $"))
percent = float(input("Tip percent (e.g. 18): "))
people = int(input("Number of people: "))

tip = bill * percent / 100
total = bill + tip
print(f"Each person pays: ${total / people:.2f}")