O'Reilly Introduction to Python/Section 1/Windows set up Python



We are going to install Python version 2.7.5.

If you already have Python installed, check the Python version: if the version is between Python 2.5 and Python 2.7, you can use it for this class and can skip to setting your Path.

If you need help or have questions during installation, don't hesitate to ask!

Download and install Python
 Click http://python.org/ftp/python/2.7.5/python-2.7.5.msi and choose "run" if you have the option to. Otherwise, save it to your Desktop, then minimize windows to see your desktop, and double click on it to start the installer. Follow the installer instructions to completion. Open a terminal (we will be doing this multiple times, so make a note of how to do this!):
 * On Windows Vista or Windows 7: click on the Start menu (the Windows logo in the lower left of the screen), type  into the Search field directly above the Start menu button, and click on "cmd" in the search results above the Search field.
 * On Windows XP: click on the Start menu (the Windows logo in the lower left of the screen), click on "Run...", type  into the text box, and hit enter.

You have started a terminal prompt. This terminal prompt is another way of navigating your computer and running programs -- just textually instead of graphically. We are going to be running Python and Python scripts from this terminal prompt.  At this  prompt that appears, test your Python installation by typing:

\Python27\python.exe

and pressing Enter. You should see something like Python 2.7.5 (r271:86832, ...) on win32 Type "help", "copyright", "credits" or "license" for more information. >>>

You just started Python! The  indicates that you are at a new type of prompt -- a Python prompt. The terminal prompt lets you navigate your computer and run programs, and the Python prompt lets you write and run Python code interactively.

 To exit the Python prompt, type

exit

and press Enter. This will take you back to the Windows command prompt (the  you saw earlier). 

Put Python on the PATH
You might have noticed that you typed a "full path" to the Python application above when launching Python ( is the application, but we typed  ). In this step, you will configure your computer so that you can run Python without typing the Python27 directory name.

Get to System Properties

 * 1) Open up "My Computer"  by clicking on the Start menu or the Windows logo in the lower-left hand corner, and navigate to "My Computer" (for Windows XP) or "Computer" (For Vista and Windows 7).
 * 2) Right-click on the empty space in the window, and choose Properties.

If you're using XP
A window labeled "System Properties" will pop up.


 * 1) Click the "Advanced" tab.

If you're not using XP
A window labeled "View basic information about your computer" will appear.


 * 1) In this window, click "Advanced system settings"

A window with the title "System Properties" will appear.

Edit the Path

 * 1) Within System Properties, make sure you are in the tab labeled "Advanced".
 * 2) Click the button labeled "Environment Variables".
 * 3) * A window labeled "Environment Variables" will appear.
 * 4) In this window, the screen is split between "User variables" and "System variables". Within "System variables", scroll down and find the one labeled Path. Click the "Edit..." button.
 * 5) * A window with the "Variable name" and the "Variable value" should appear. The "Variable value" will already have some text in it; click in the box to unhighlight it (we don't want to accidentally delete that text).
 * 6) In the "Variable value" box, scroll to the end. Add the following text, and hit OK. Make sure to include the semicolon at the start! ;c:\python27\;c:\python27\scripts
 * 7) Press "OK" to close out the system properties window.
 * 8) Test your change:
 * 9) Open up a new command prompt: you do this the same way you did above when installing python. This needs to be a new command prompt because the changes you just made didn't take affect in prompts that were already open.
 * 10) Type   into the command prompt to start Python
 * 11) Notice that you now get a Python interpreter, indicated by the change to a   prompt.
 * 12) Exit the Python prompt by typing exit and hitting enter. Now you're back at the Windows command prompt.

Success!
You have Python installed and configured.



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