Python Roadmap

Learn Python step by step — 153 free lessons with spaced repetition and active recall on RetainHQ, so what you study actually sticks.

Lessons

• ABC Module and Abstract Methods
• *args and **kwargs
• Assertions and pytest.raises
• Async context managers
• Black: auto-formatting
• Branching strategies: feature, main, release
• break, continue, loop else clause
• __call__: Making Objects Callable
• Class Creation and Instantiation
• Class decorators
• Closure Mechanics
• Closures
• Time Complexity of Collection Operations
• Concurrency vs Parallelism
• conftest.py: shared fixtures
• contextlib.contextmanager decorator
• Conventional commits spec
• Coroutines, async / await
• collections.Counter
• cProfile for performance profiling
• CSV files with the csv module
• Custom exception classes
• Custom Iterator Class
• @dataclass Basics
• field() and default_factory
• Dataclasses vs Pydantic
• Decorator Factories with Arguments
• Function Decorators
• collections.defaultdict
• Dependency isolation strategies
• collections.deque
• Dictionary and set comprehensions
• Dictionaries: operations and use cases
• Dependency Inversion Principle
• python-dotenv for .env files
• Duck Typing
• Dynamic typing and type()
• else and finally blocks
• __enter__ and __exit__
• Loop idioms: range, enumerate, zip
• os.environ and Environment Variables
• Everything is an object in Python
• Exception chaining with raise from
• Factory pattern
• Reading and writing files with open()
• First-class functions: passing and returning functions
• Fixtures and fixture scope
• Frozen Dataclasses
• Defining functions and return values
• functools: lru_cache, partial, reduce
• functools.wraps and preserving metadata
• Garbage Collection and Cyclic References
• Generator expressions vs list comprehensions
• Generator send() for Two-Way Communication
• Generic Types
• if/elif/else and Python truthiness
• Single inheritance and super()
• __init__ and __new__
• Instance variables vs class variables
• Interface patterns in Python
• Integer and String Interning
• is vs == : Identity vs Equality
• Interface Segregation Principle
• iter() and next() builtins
• __iter__ and __next__
• The Iterable Protocol
• Iterator Protocol and StopIteration
• itertools essentials
• JSON serialization with the json module
• Keyword-only and positional-only parameters
• Lambda functions and when to use them
• Late Binding Closures Gotcha
• Layered architecture
• Lazy Evaluation and Memory Efficiency
• __len__, __getitem__, __setitem__
• Lexical Scope and Free Variables
• List Comprehensions
• Lists: indexing, slicing, methods
• Log Rotation with RotatingFileHandler
• Loggers, Handlers, and Formatters
• Logging levels and basicConfig
• for and while loops
• Liskov Substitution Principle
• match-case statement
• Method Overriding
• Instance, Class, and Static Methods
• Mocking external API calls
• Modular design and separation of concerns
• MRO: Method Resolution Order (C3 linearization)
• Multiple Inheritance & The Diamond Problem
• Multiprocessing for CPU-bound work
• Mutable default argument pitfall
• Mutable vs immutable objects
• Mypy: static type checking
• Nested comprehensions
• Object identity: id() and memory references
• Observer pattern
• Open/Closed Principle
• Operator Overloading: __add__, __eq__, __lt__
• Optional and Union Types
• Package structure and __init__.py
• patch as decorator and context manager
• pathlib for filesystem paths
• pdb and breakpoint()
• Poetry: dependency management basics
• __post_init__ Processing
• Pre-commit hooks setup
• Primitive types: int, float, bool, str
• Property Decorator
• Structural Subtyping with Protocols
• Provider abstraction pattern
• Pull request workflow
• pyproject.toml and project metadata
• @pytest.mark.parametrize
• Raising exceptions with raise
• Reading stack traces
• Rebase vs merge
• Reference Counting in CPython
• Regular expressions with re
• Ruff: linting and import sorting
• LEGB rule: variable scope in Python
• Service-repository pattern
• Sets: operations and use cases
• Shallow vs Deep Copy
• Singleton pattern
• Slicing lists & strings
• __slots__ for Memory Optimization
• Sorting with sorted and key=
• Single Responsibility Principle
• Stacking Multiple Decorators
• Stateful Functions Using Closures
• __str__ vs __repr__
• Strategy pattern
• Strings & string methods
• Structured Logging with JSON
• Ternary expressions
• Test discovery and naming conventions
• asyncio and the event loop
• The GIL (Global Interpreter Lock)
• Threading for I/O-bound work
• Threading vs Multiprocessing
• try/except with specific exception types
• Tuples: immutability and use cases
• TYPE_CHECKING for Avoiding Circular Imports
• Type conversion: implicit vs explicit casting
• Basic Annotations
• Protocols for Structural Typing
• TypeVar and Generic Functions
• unittest.mock: Mock and MagicMock
• When async actually helps
• The 'with' Statement and Resource Management
• yield from and generator delegation
• yield keyword and generator functions