# pytudes

"An *étude* (a French word meaning *study*) is an instrumental musical composition, usually short, of considerable difficulty, and designed to provide practice material for perfecting a particular musical skill." — [Wikipedia](https://en.wikipedia.org/wiki/%C3%89tude)

This project contains **pytudes**—Python programs for perfecting programming skills.

Some are in Jupyter (IPython) notebooks, some in `.py` files. You can view the files here on github, or click the **NB** link to view them on [nbviewer](http://nbviewer.jupyter.org/) (which sometimes works better). If you want to *run* the notebooks, not just view them, you can clone the project, or run all the notebooks online by clicking this button: [![Binder](https://mybinder.org/badge.svg)](https://mybinder.org/v2/gh/norvig/pytudes/master), or click the **DN** link to run each individual notebook on   [deepnote](https://beta.deepnote.org/).

# Index of Jupyter (IPython) Notebooks



|Programming Examples|
|---|
|[Advent of Code 2017](ipynb/Advent%202017.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Advent%202017.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FAdvent%25202017.ipynb)**<br>*Puzzle site with a coding puzzle each day for Advent 2017.*|
|[Advent of Code 2016](ipynb/Advent%20of%20Code.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Advent%20of%20Code.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FAdvent%2520of%2520Code.ipynb)**<br>*Puzzle site with a coding puzzle each day for Advent 2016*.|
|[Project Euler Utilities](ipynb/Project%20Euler%20Utils.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Project%20Euler%20Utils.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FProject%2520Euler%2520Utils.ipynb)**<br>*My utility functions for the Project Euler problems, including `Primes` and `Factors`.*|
|[Translating English Sentences into Propositional Logic Statements](ipynb/PropositionalLogic.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/PropositionalLogic.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FPropositionalLogic.ipynb)**<br>*Automatically converting informal English sentences into formal Propositional Logic.*|
|[Beal's Conjecture Revisited](ipynb/Beal.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Beal.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FBeal.ipynb)**<br>*A search for counterexamples to Beal's Conjecture*|
|[WWW: Who Will Win (NBA Title)?](ipynb/WWW.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/WWW.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FWWW.ipynb)**<br>*Computing the probability of winning the NBA title, for my home town Warriors, or any other team.*|
|[Pickleball Tournament](ipynb/Pickleball.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Pickleball.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FPickleball.ipynb)**<br>*Scheduling a doubles tournament fairly and efficiently.*|
|[Conway's Game of Life](ipynb/Life.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Life.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FLife.ipynb)**<br>*The cellular automata zero-player game.*|
|[A Chaos Game with Triangles](ipynb/Sierpinski.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Sierpinski.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FSierpinski.ipynb)**<br>*A surprising appearance of the Sierpinski triangle in a random walk between vertexes.*|
|[Generating Mazes](ipynb/Maze.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Maze.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FMaze.ipynb)**<br>*Make a maze by generating a random tree superimposed on a grid.*|
|[Can't Stop](ipynb/Cant-Stop.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Cant-Stop.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FCant-Stop.ipynb)**<br>*Optimal play in a dice board game.*|
|[Bike Speed Versus Grade](ipynb/Bike%20Speed%20versus%20Grade.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Bike%20Speed%20versus%20Grade.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FBike%2520Speed%2520versus%2520Grade.ipynb)**<br>*How fast can I bike as the route gets steeper?*|
|[Properly Ordered Card Hands](ipynb/Orderable%20Cards.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Orderable%20Cards.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FOrderable%2520Cards.ipynb)**<br>*Can you get your hand of cards into a nice order with just one move?*|

|Logic and Number Puzzles|
|---|
|[When is Cheryl's Birthday?](ipynb/Cheryl.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Cheryl.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FCheryl.ipynb)**<br>*Solving the "Cheryl's Birthday" logic puzzle.*|
|[When Cheryl Met Eve: A Birthday Story](ipynb/Cheryl-and-Eve.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Cheryl-and-Eve.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FCheryl-and-Eve.ipynb)**<br>*Inventing new puzzles in the Style of Cheryl's Birthday.*|
|[The Devil and the Coin Flip Game](ipynb/Coin%20Flip.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Coin%20Flip.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FCoin%2520Flip.ipynb)**<br>*How to beat the Devil at his own game.*|
|[The Puzzle of the Misanthropic Neighbors](ipynb/Mean%20Misanthrope%20Density.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Mean%20Misanthrope%20Density.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FMean%2520Misanthrope%2520Density.ipynb)**<br>*How crowded will this neighborhood be, if nobody wants to live next door to anyone else?*|
|[Four 4s, Five 5s, and Countdown to 2016](ipynb/Countdown.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Countdown.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FCountdown.ipynb)**<br>*Solving the equation 10 _ 9 _ 8 _ 7 _ 6 _ 5 _ 4 _ 3 _ 2 _ 1 = 2016. From an Alex Bellos puzzle.*|
|[Sicherman Dice](ipynb/Sicherman%20Dice.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Sicherman%20Dice.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FSicherman%2520Dice.ipynb)**<br>*Find a pair of dice that is like a regular pair of dice, only different.*|
|[Sol Golomb's Rectangle Puzzle](ipynb/Golomb-Puzzle.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Golomb-Puzzle.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FGolomb-Puzzle.ipynb)**<br>*A Puzzle involving placing rectangles of different sizes inside a square. Bonus: cryptarithmetic.*|
|[The Riddler: Battle Royale](ipynb/Riddler%20Battle%20Royale.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Riddler%20Battle%20Royale.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FRiddler%2520Battle%2520Royale.ipynb)**<br>*A puzzle involving allocating your troops and going up against an opponent.*|

|Word Games|
|---|
|[xkcd 1970: Name Dominoes](ipynb/xkcd-Name-Dominoes.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/xkcd-Name-Dominoes.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2Fxkcd-Name-Dominoes.ipynb)**<br>*Lay out dominoes legally; the dominoes have people names, not numbers.*|
|[Ghost](ipynb/Ghost.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Ghost.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FGhost.ipynb)**<br>*The word game Ghost (add letters, try to avoid making a word).*|
|[World's Longest Palindrome](ipynb/pal3.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/pal3.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2Fpal3.ipynb)**<br>*Searching for a long Panama-style palindrome, this time letter-by-letter.*|
|[Refactoring a Crossword Game Program](ipynb/Scrabble.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Scrabble.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FScrabble.ipynb)**<br>*Refactoring the Scrabble / Word with Friends game from Udacity 212.*|
|[xkcd 1313: Regex Golf](ipynb/xkcd1313.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/xkcd1313.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2Fxkcd1313.ipynb)**<br>*Find the smallest regular expression; inspired by Randall Monroe.*|
|[xkcd 1313: Regex Golf (Part 2: Infinite Problems)](ipynb/xkcd1313-part2.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/xkcd1313-part2.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2Fxkcd1313-part2.ipynb)**<br>*Regex Golf: better, faster, funner. With Stefan Pochmann.*|
|[Let's Code About Bike Locks](ipynb/Fred%20Buns.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Fred%20Buns.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FFred%2520Buns.ipynb)**<br>*A tale of a bicycle combination lock that uses letters instead of digits. Inspired by Bike Snob NYC.*|
|[Gesture Typing](ipynb/Gesture%20Typing.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Gesture%20Typing.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FGesture%2520Typing.ipynb)**<br>*What word has the longest path on a gesture-typing smartphone keyboard?*|
|[How to Do Things with Words, or Statistical Natural Language Processing in Python](ipynb/How%20to%20Do%20Things%20with%20Words.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/How%20to%20Do%20Things%20with%20Words.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FHow%2520to%2520Do%2520Things%2520with%2520Words.ipynb)**<br>*Spelling Correction, Secret Codes, Word Segmentation, and more: grab your bag of words.*|

|Math Concepts|
|---|
|[A Concrete Introduction to Probability](ipynb/Probability.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Probability.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FProbability.ipynb)**<br>*Code and examples of the basic principles of Probability Theory.*|
|[Probability, Paradox, and the Reasonable Person Principle](ipynb/ProbabilityParadox.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/ProbabilityParadox.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FProbabilityParadox.ipynb)**<br>*Some classic paradoxes in Probability Theory, and how to think about disagreements.*|
|[Symbolic Algebra, Simplification, and Differentiation](ipynb/Differentiation.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Differentiation.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FDifferentiation.ipynb)**<br>*A computer algebra system that  manipulates expressions, including symbolic differentiation.*|
|[Economics Simulation](ipynb/Economics.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Economics.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FEconomics.ipynb)**<br>*A simulation of a simple economic game.*|
|[How to Count Things](ipynb/How%20To%20Count%20Things.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/How%20To%20Count%20Things.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FHow%2520To%2520Count%2520Things.ipynb)**<br>*Combinatorial math: how to count how many things there are, when there are a lot of them.*|
|[Euler's Sum of Powers Conjecture](ipynb/Euler's%20Conjecture.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Euler's%20Conjecture.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FEuler's%2520Conjecture.ipynb)**<br>*Solving a 200-year-old puzzle by finding integers that satisfy a<sup>5</sup> + b<sup>5</sup> + c<sup>5</sup> + d<sup>5</sup> = e<sup>5</sup>.*|

|Computer Science Algorithms and Concepts|
|---|
|[BASIC Interpreter](ipynb/BASIC.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/BASIC.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FBASIC.ipynb)**<br>*How to write an interpreter for the BASIC programming language.*|
|[Bad Grade, Good Experience](ipynb/Snobol.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Snobol.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FSnobol.ipynb)**<br>*As a student, did you ever get a bad grade on a programming assignment? (Snobol, Concordance)*|
|[The Convex Hull Problem](ipynb/Convex%20Hull.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/Convex%20Hull.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FConvex%2520Hull.ipynb)**<br>*A classic Computer Science Algorithm.*|
|[The Traveling Salesperson Problem](ipynb/TSP.ipynb)&nbsp; &nbsp; **[NB](http:/nbviewer.jupyter.org/github/norvig/pytudes/blob/master/ipynb/TSP.ipynb)**, **[DN](https://beta.deepnote.org/launch?template=python_3.6&url=https%3A%2F%2Fgithub.com%2Fnorvig%2Fpytudes%2Fblob%2Fmaster%2Fipynb%2FTSP.ipynb)**<br>*Another of the classics.*|

# Index of Python Files

| **File** | **Description** | **Documentation**|
|:--------|:-------------------|----|
|[SET.py](https://github.com/norvig/pytudes/blob/master/py/SET.py)|Analyze the card game [SET](http://www.setgame.com/set).|[SET.html](http://norvig.com/SET.html)|
|[beal.py](https://github.com/norvig/pytudes/blob/master/py/beal.py)|Search for counterexamples to Beal's Conjecture|[beal.html](http://norvig.com/beal.html)
|[docex.py](https://github.com/norvig/pytudes/blob/master/py/docex.py)|A framework for running unit tests, similar to `doctest`.|
|[ibol.py](https://github.com/norvig/pytudes/blob/master/py/ibol.py)|An Exercise in Species Barcoding|[ibol.html](http://norvig.com/ibol.html)
|[lettercount.py](https://github.com/norvig/pytudes/blob/master/py/lettercount.py)|Convert Google Ngram Counts to Letter Counts|[mayzner.html](http://norvig.com/mayzner.html)
|[lis.py](https://github.com/norvig/pytudes/blob/master/py/lis.py)|Lisp Interpreter written in Python|[lispy.html](http://norvig.com/lispy.html)
|[lispy.py](https://github.com/norvig/pytudes/blob/master/py/lispy.py)|Even Better Lisp Interpreter written in Python|[lispy2.html](http://norvig.com/lispy2.html)
|[lispytest.py](https://github.com/norvig/pytudes/blob/master/py/lispytest.py)|Tests for Lisp Interpreters|
|[pal.py](https://github.com/norvig/pytudes/blob/master/py/pal.py)|Find long palindromes|[palindrome.html](http://norvig.com/palindrome.html)
|[pal2.py](https://github.com/norvig/pytudes/blob/master/py/pal2.py)|Find longer palindromes|[palindrome.html](http://norvig.com/palindrome.html)
|[pal3.py](https://github.com/norvig/pytudes/blob/master/py/pal3.py)|Find even longer palindromes|[palindrome.html](http://norvig.com/palindrome.html)
|[py2html.py](https://github.com/norvig/pytudes/blob/master/py/py2html.py)|Pretty-printer to format Python files as html|
|[spell.py](https://github.com/norvig/pytudes/blob/master/py/spell.py)|Spelling corrector|[spell-correct.html](http://norvig.com/spell-correct.html)
|[sudoku.py](https://github.com/norvig/pytudes/blob/master/py/sudoku.py)|Program to solve sudoku puzzles|[sudoku.html](http://norvig.com/sudoku.html)
|[testaccum.py](https://github.com/norvig/pytudes/blob/master/py/testaccum.py)|Tests for my failed Python `accumulation display` proposal|[pyacc.html](http://norvig.com/pyacc.html)
|[yaptu.py](https://github.com/norvig/pytudes/blob/master/py/yaptu.py)|Yet Another Python Templating Utility|

# Etudes for Programmers

I got the idea for the "etudes" part of the name from
this [1978 book](https://books.google.com/books/about/Etudes_for_programmers.html?id=u89WAAAAMAAJ)
by [Charles Wetherell](http://demin.ws/blog/english/2012/08/25/interview-with-charles-wetherell/)
that was very influential to me when I was first learning to program.

![](https://images-na.ssl-images-amazon.com/images/I/51ZnZH29dvL._SX394_BO1,204,203,200_.jpg)