IPython, which is available at http://ipython.org/, is a free, open source project available for Linux, Unix, Mac OS X, and Windows. The IPython authors only request that you cite IPython in any scientific work where IPython was used. It provides the following components, among others:

You can try IPython in cloud without installing it on your system, by going to the following URL: http://www.pythonanywhere.com/try-ipython/. There is a slight delay compared to locally installed software; so this is not as good as the real thing. However, most of the features available in the IPython interactive shell seem to be available. They also have a Vi (m) editor, which if you like vi, is of course great. You can save and edit files from your IPython sessions. The author of this book doesn't care much about other editors, such as the one that starts with E and ends with macs. This should, however, not be a problem.