01 · Build the script
Collect expenses in memory, validate amounts, group by category, and print a total through an interactive command loop.
For absolute beginners
Python Foundations Workshop
Write your first script, practice one concept at a time, and build the same Expense Tracker twice as your skills grow.
1,000pages
310concept demos
65practice problems
58workshops
2milestone projects
13 chapters
Find a topic
13 chapters
01 Environment and first programs
Install an interpreter, choose it in VS Code, and run a saved script from an editor and a terminal. Compare the interpreter and working directory when the two routes behave differently.
Pages 9–41 · 5 demos · 5 practice · 4 workshops02 Variables and data types
Give values names, inspect their types, preserve identifiers as text, and convert numeric inputs explicitly. Keep units in variable names and separate calculations from display.
Pages 42–128 · 32 demos · 5 practice · 4 workshops03 Strings and f-strings
Read and reshape text. Use indexes and slices to locate fields, string methods to normalize input, and f-strings to produce readable labels.
Pages 129–191 · 20 demos · 5 practice · 4 workshops04 Operators, Booleans and conditionals
Use Boolean expressions to model a rule. Turn decisions into branches, check exact boundaries, and protect operations that require valid inputs.
Pages 192–252 · 19 demos · 5 practice · 4 workshops05 Collections
Pick collections by purpose. Use a list for sequence, tuple for fixed fields, dictionary for keyed lookup, and set for membership. Watch when mutations are shared.
Pages 253–380 · 51 demos · 5 practice · 5 workshops06 Loops and comprehensions
Process repeated data with for and while. Stop or skip intentionally, pair and number records, and switch to comprehensions when the transformation stays clear.
Pages 381–496 · 45 demos · 5 practice · 5 workshops07 Functions
Move calculations into reusable functions. Design parameters and returns before the implementation, test boundaries, and watch scope and shared mutable values.
Pages 497–616 · 47 demos · 5 practice · 5 workshops08 Type hints
Annotate expected shapes using built-in generics, unions and aliases. Treat hints as communication to people and tools. Keep parsing and runtime checks explicit.
Pages 638–678 · 9 demos · 5 practice · 4 workshops09 Error handling and debugging
Reproduce a failure in a small fixture, read the final traceback line and its call stack, then catch the specific condition that your code can recover from.
Pages 679–728 · 12 demos · 5 practice · 5 workshops10 Files, JSON and paths
Work with paths independently of file contents. Read and write UTF-8 text, decode JSON, verify its shape, and keep missing-file and corrupt-data cases distinct.
Pages 729–786 · 16 demos · 5 practice · 5 workshops11 Standard library essentials
Use the standard library for arithmetic, dates, grouping, sampling, statistics and more. Choose modules by the behavior you need and exercise boundaries with fixed fixtures.
Pages 787–851 · 21 demos · 5 practice · 4 workshops12 Virtual environments and packaging
Separate files into importable modules and packages. Create a virtual environment, use its interpreter for pip, and connect project metadata to a runnable entry point.
Pages 852–890 · 8 demos · 5 practice · 4 workshops13 Classes and object-oriented basics
Give a model a clear state contract. Use instance methods, class constructors, static helpers and representations intentionally, then organize a program around cooperating objects.
Pages 891–966 · 25 demos · 5 practice · 5 workshops
Build in two milestones
One Expense Tracker, two versions
02 · Build the package
Add classes, versioned JSON, error handling, a virtual environment, tests, and an optional Rich table display.
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The PDF and ZIP include every runnable demo, practice and workshop solution, both tracker projects, and a curriculum index. Use Python 3.11 or newer.
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