Python
Code Quality: PEP 8, Docstrings and Clean Code
Code is read far more often than it is written. Consistent style, honest names and clear structure are what make the second reading cheap.
Python
A complete core Python path: syntax, data types, operators, strings, control flow, collections, functions, exceptions, files, modules, the standard library, OOP, iterators, generators, decorators, internals, concurrency, regular expressions, testing, typing, performance, security, problem solving, projects, interview preparation and exams.
110 notes in 33 topics
Topics in Python
Basics 5
Data Types 4
Operators 5
Strings 5
Control Flow 5
Lists 3
Tuples 2
Sets 2
Dictionaries 3
Comprehensions 2
Functions 4
Advanced Functions 2
Recursion 2
Exception Handling 4
File Handling 4
Modules 3
Standard Library 6
OOP 5
Advanced OOP 5
Iterators and Generators 3
Decorators 2
Context Managers 1
Descriptors and Dataclasses 2
Python Internals 4
Concurrency 4
Regular Expressions 3
Serialization 2
Command Line Python 2
Testing and Debugging 3
Type Hints 2
Performance 3
Python Security 2
DSA with Python 6
Notes
Python
Type Hints: The Basics
Annotations describe what a function expects and returns. Python does not enforce them, and that is the point: they are documentation a tool can check...
Python
Advanced Typing: Generics, Protocol and TypedDict
Type variables let one function work with any type while keeping the relationship between input and output. Protocol describes a shape, and TypedDict...
Python
Complexity and Choosing Data Structures
Big-O describes how work grows with input size. Choosing the right container is worth more than every micro-optimisation combined.
Python
Profiling: timeit, cProfile and tracemalloc
Measure before optimising. Guessing where a program spends its time is wrong often enough that the habit is worth breaking permanently.
Python
Optimisation Techniques
Once the algorithm is right, a handful of techniques reliably help: build less, look up less, let C do the loop, and cache what repeats.
Python
Input Validation, Files and Secrets
Most security problems come from trusting input, trusting paths and storing secrets in the wrong place. Each has a standard, boring, correct answer.
Python
Dangerous Execution and Injection
eval, exec, shell commands, string built queries and pickle all take text and turn it into action. Each has a safe alternative that costs almost nothi...
Python
Searching Algorithms
Linear search checks everything; binary search halves the problem each step. Knowing when the second is possible is worth more than either implementat...
Python
Sorting Algorithms
Python sorts for you in n log n. Implementing bubble, insertion, merge and quick sort is still worth doing, because it teaches how algorithms are comp...
Python
Stacks, Queues and Linked Lists
Three linear structures defined by where you may add and remove items. Python gives you two of them almost for free; the third is worth building once.
Python
Hashing and Frequency Counting
A dictionary turns "have I seen this?" and "how many of these?" from an O(n) scan into an O(1) lookup. That single change solves a large share of inte...