Chicago Python Workshop/Setup/Windows Python scripts

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< Chicago Python Workshop‎ | Setup
Revision as of 05:45, 24 November 2012 by imported>Codersquid
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We are going to practice writing and running Python scripts.

Start your text editor

  1. Launch the Notepad++ text editor. See the Windows text editor setup instructions for the steps to do this.
  2. Start a new, blank text file.

Write and save a short Python script

  1. Add the following line to your new text file:
print "Hello World!"
  1. Saving the script
    1. Click either the Save button or going to File > Save
    2. Then, navigate to your Desktop folder, which will be under C:\Documents and Settings\<username> or C:\Users\<username>.
    3. Once you've double clicked on the Desktop folder, then click the new folder icon. Then name it python. This is where we will keep all our python code and projects, so that it's easy to find.
    4. Then click through the python folder you just created, and save the file as hello.py in this python directory. The .py extension indicates that this file contains Python code.

Run the script

  1. Start a new command prompt. See the terminal navigation on Windows instructions for the steps to do this. Recall that a terminal prompt will look like C:\ and a Python prompt will look like >>>. Make sure you are at a terminal prompt and not a Python prompt; if you are at a Python prompt, you can type exit() on a line by itself and then hit enter to exit Python and return to a terminal prompt.
  2. Navigate to your python directory, which is in your desktop directory, from a command prompt, using the dir and cd commands. See the terminal navigation on Windows instructions for a refresher on using these commands. Don't hesitate to get help from a staff member on this step if you need it -- it's a new way of navigating your computer, so it may be unintuitive at first!
  3. Once you are in your python directory, you'll see hello.py in the output of dir.
  4. Type
python hello.py

and hit enter. Doing this will cause Python to execute the contents of that script -- it should print "Hello World!" to the screen. What you've done here is run the Python application with an argument -- the name of a file, in this case "hello.py". Python knows that when you give it a file name as an argument, it should execute the contents of the provided file. You get the same result as if you typed

print "Hello World!"

at a Python prompt and hit enter.

Success

You created and ran your first Python script!

  • When you run the python command by itself, you start a Python prompt. You can execute Python code interactively at that prompt.
  • When you run the python command with a file name as an argument, Python executes the Python code in that file.