Scripts/Programs

You might have guessed that programmers don’t actually re-type everything every time the computer loads. There must be a way for a programmer to save the instructions we’ve been typing into the interpreter and run them later.

While other languages have more involved setup, the steps for creating and running a Python script (a small program) are:

  • save the commands as a plain text file to the hard-disk
  • run the plain-text file using python from the command line

Creating a Script

In Idle or Pyscripter create a new file with the content:

print "Hello, World!"

and save that to your home directory (H:) as helloworld.py.

Note

If you are using Python 3, the content should be:

print("Hello, World!")

Getting to the Command Prompt

We’ll use the PowerShell environment from Microsoft as our command line.

  • Press and hold the “Windows” key, and hit the “R” key
    • a dialog will appear from which you can run commands
  • Type powershell <enter>
  • You should see a command prompt
  • Change directory to your home directory
PS c:\Users\mcfletch> h:
PS h:\somewhere> cd \
PS h:\>
  • If you list the directory you should see your Python script
PS h:\> dir

and we can try to run it with:

PS h:\> python helloworld.py
Hello, World!