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Learn Python, one small idea at a time.

114 short chapters, each with code you can run and change right on the page. No install, no account, nothing to set up.

Start with introduction Open the editor Exercises

Basics

14

Introduction Get Started Syntax Comments Variables Variable Names Multiple Assignment Global Variables Data Types Numbers Casting Booleans Operators User Input

Strings

9

Strings Slicing Modify Strings Concatenation f-Strings String Formatting Escape Characters String Methods Text and Unicode

Collections

19

Lists List Access Change Items Add Items Remove Items Loop Lists List Comprehension Sort Lists Copy Lists Join Lists List Methods Tuples Sets Dictionaries Nested Dictionaries Dictionary Methods Set Methods Dict and Set Comprehensions The collections Module

Control flow

5

If...Else Match While Loops For Loops Break and Continue

Functions

11

Functions Arguments args and kwargs Default Values Return Values Scope Recursion Lambda Decorators Generators Closures

Classes and objects

11

Classes and Objects The __init__ Method The __str__ Method Methods self Inheritance Polymorphism Iterators Dataclasses Enums Magic Methods

Modules and the standard library

9

Modules PIP Dates Math JSON RegEx itertools os and sys Random Numbers

Files and errors

9

File Handling Read Files Write Files Delete Files Try...Except Raising Exceptions CSV Files Context Managers Paths with pathlib

Beyond the basics

13

Virtual Environments Type Hints Async Basics NumPy Intro Pandas Intro Matplotlib Intro Working with APIs Testing Logging Command-line Arguments Debugging SQLite Packaging

Machine learning

14

What Machine Learning Is Your First Model Features and Labels Train and Test Split Classification Regression Evaluating a Model Overfitting and Underfitting Preprocessing Pipelines Clustering Neural Networks Saving and Using a Model Where It Goes Wrong