Think Python: How to Think Like a Computer Scientist

Stack Diagrams To keep track of which variables can be used where, it is sometimes useful to draw a ...

print(cat) NameError: name 'cat' is not defined This list of functions is called a traceback ...

Fruitful Functions and Void Functions Some of the functions we have used, such as the math functions, r ...

Why Functions? It may not be clear why it is worth the trouble to divide a program into functions. There are se ...

Debugging One of the most important skills you will acquire is debugging. Although it can be frustrating, deb ...

Glossary function: A named sequence of statements that performs some useful operation. Functions may or m ...

A special value returned by void functions. module: A file that contains a collection of related funct ...

Exercises Exercise 3-1. Write a function named right_justify that takes a string named s as a param ...

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Chapter 4. Case Study: Interface Design This chapter presents a case study that demonstrates a pro ...

The turtle Module To check whether you have the turtle module, open the Python interpreter and type: >>> i ...

bob.lt(90) bob.fd(100) When you run this program, you should see bob move east and then north, leaving two l ...

Simple Repetition Chances are you wrote something like this: bob.fd(100) bob.lt(90) bob.fd(100) bob.lt(90) bob.fd(100) ...

Exercises The following is a series of exercises using TurtleWorld. They are meant to be fun, but they ...

Encapsulation The first exercise asks you to put your square-drawing code into a function definition an ...

Generalization The next step is to add a length parameter to square. Here is a solution: def square(t, len ...

Interface Design The next step is to write circle, which takes a radius, r, as a parameter. Here is ...

Refactoring When I wrote circle, I was able to reuse polygon because a many-sided polygon is a good approx ...

that you have learned something. ...