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Installing Python

❝ Tempora mutantur nos et mutamur in illis. (Times change, and we change with them.) ❞
— ancient Roman proverb

Diving in

Welcome to Python 3. Let's dive in. In this chapter, you'll install the version of Python 3 that's right for you.

Which Python Is Right For You?

The first thing you need to do with Python is install it. Or do you?

If you're using an account on a hosted server, your ISP may have already installed Python 3. If you’re running Linux at home, you may already have Python 3, too. Most popular GNU/Linux distributions come with Python 2 in the default installation; a small but growing number of distributions also include Python 3. (As you’ll see in this chapter, you can have more than one version of Python installed on your computer.) Mac OS X includes a command-line version of Python 2, but as of this writing it does not include Python 3. Microsoft Windows does not come with any version of Python. But don’t despair! You can point-and-click your way through installing Python, regardless of what operating system you have.

The easiest way to check for Python 3 on your Linux or Mac OS X system is to get to a command line. On Linux, look in your Applications menu for a program called Terminal. (It may be in a submenu like Accessories or System.) On Mac OS X, there is an application called Terminal.app in your /Application/Utilities/ folder.

Once you’re at a command line prompt, just type python3 (all lowercase, no spaces) and see what happens. On my home Linux system, Python 3 is already installed, and this command gets me into the Python interactive shell.

mark@atlantis:~$ python3
Python 3.0.1+ (r301:69556, Apr 15 2009, 17:25:52)
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>

(Type exit and press ENTER to exit the Python interactive shell.)

My web hosting provider also runs Linux and provides command-line access, but my server does not have Python 3 installed. (Boo!)

mark@manganese:~$ python3
bash: python3: command not found

So back to the question that started this section, “Which Python is right for you?” The answer is whichever one runs on the computer you already have.

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Installing on Microsoft Windows

Windows comes in two architectures these days: 32-bit and 64-bit. Of course, there are lots of different versions of Windows — XP, Vista, Windows 7 — but Python runs on all of them. The more important distinction is 32-bit v. 64-bit. If you have no idea what architecture you’re running, it’s probably 32-bit.

Visit python.org/download/ and download the appropriate Python 3 Windows installer for your architecture. Your choices will look something like this:

Python 3.1 Windows installer (Windows binary — does not include source)
Python 3.1 Windows AMD64 installer (Windows AMD64 binary — does not include source)

I don’t want to include direct download links here, because minor updates of Python happen all the time and I don’t want to be responsible for you missing important updates. You should always install the most recent version of Python 3.x unless you have some esoteric reason not to.

Once your download is complete, double-click the .msi file. Windows will pop up a security alert, since you’re about to be running executable code. The official Python installer is digitally signed by the Python Software Foundation, the non-profit corporation that oversees Python development. Don’t accept imitations!
Click the Run button to launch the Python 3 installer.
The first question the installer will ask you is whether you want to install Python 3 for all users or just for you. The default choice is “install for all users,” which is the best choice unless you have a good reason to choose otherwise. (One possible reason why you would want to “install just for me” is that you are installing Python on your company’s computer and you don’t have administrative rights on your Windows account. But then, why are you installing Python without permission from your company’s Windows administrator? Don’t get me in trouble here!)
Click the Next button to accept your choice of installation type.

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Installing on Mac OS X

FIXME

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Installing on Ubuntu Linux

FIXME

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Installing on Other Platforms

FIXME

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Python Editors and IDEs

FIXME

http://wiki.python.org/moin/PythonEditors
http://wiki.python.org/moin/IntegratedDevelopmentEnvironments
http://pydev.sourceforge.net/
http://www.activestate.com/komodo/
http://www.activestate.com/activepython/

☜ ☞