Python from the Start

The language, from nothing to writing your own modules. Every other guide depends on this one.

Complete 21 notebooks 21 written

Before this guide: None. If you have never written a line of code, start here.

The notebooks

Open in Colab runs a notebook in your browser, and Read shows it on GitHub without running it. Every notebook runs on its own, and the answers to its exercises are in a separate notebook, linked as Solutions.

1	Running PythonColab, cells, print, and the read-eval loop	Open in Colab Read Solutions
2	Values and VariablesAssignment, names, and what a variable actually is	Open in Colab Read Solutions
3	Numbersint, float, integer division, and why 0.1 + 0.2 is not 0.3	Open in Colab Read Solutions
4	StringsSlicing, f-strings, methods, and immutability	Open in Colab Read Solutions
5	Regular ExpressionsPatterns, groups, and the re module	Open in Colab Read Solutions
6	Booleans and ComparisonTruthiness, and why `is` is not `==`	Open in Colab Read Solutions
7	ListsMutation, aliasing, and the copy that was not a copy	Open in Colab Read Solutions
8	Tuples and UnpackingImmutability as a feature, and multiple return values	Open in Colab Read Solutions
9	DictionariesThe workhorse. get, setdefault, and iteration order	Open in Colab Read Solutions
10	SetsMembership, deduplication, and set algebra	Open in Colab Read Solutions
11	Conditionalsif, elif, else, and the guard clause	Open in Colab Read Solutions
12	Loopsfor, while, break, continue, enumerate, zip	Open in Colab Read Solutions
13	ComprehensionsThe Python idiom, and when it stops being readable	Open in Colab Read Solutions
14	FunctionsArguments, returns, and the mutable default argument trap	Open in Colab Read Solutions
15	ScopeLocal, global, closures, and why your variable did not change	Open in Colab Read Solutions
16	Errors and ExceptionsReading a traceback, try/except, and raising your own	Open in Colab Read Solutions
17	Files and PathsReading, writing, context managers, pathlib	Open in Colab Read Solutions
18	Modules and ImportsYour own modules, the import path, and `if __name__`	Open in Colab Read Solutions
19	Environments and pipvenv, requirements, and why the tutorial broke	Open in Colab Read Solutions
20	Debuggingprint, breakpoint, and reading the error you already have	Open in Colab Read Solutions
21	Where NextA map of the other guides, and what to read for what	Open in Colab Read Solutions

Sources

Some of the ground this guide covers, including the way a variable is a name rather than a box and the several ways Python can be run, is shaped by A Whirlwind Tour of Python by Jake VanderPlas, released under a CC0 “No Rights Reserved” license. The explanations, examples and exercises here are written for this guide.