Online Python Tutor is a free educational tool that helps students overcome a fundamental barrier to learning programming: understanding what happens as the computer executes each line of a program's source code. Using this tool, a teacher or student can write a Python program directly in the web browser and visualize what the computer is doing step-by-step as it executes the program.
Welcome to the 2nd Edition of Learn Python the hard way. You can visit the companion site to the book at http://learnpythonthehardway.org/ where you can purchase digital downloads and paper versions of the book. The free HTML version of the book is available at http://learnpythonthehardway.org/book/