Learning Python, 5th Edition

Appendix D. Solutions to End-of-Part Exercises

Part I, Getting Started

See “Test Your Knowledge: Part I Exercises” in Chapter 3 for the exercises.

1. Interaction. Assuming Python is configured properly, the interaction should look something like the following (you can run this any way you like (in IDLE, from a shell prompt, and so on):

   % python
   ...copyright information lines...
   >>> "Hello World!"
   'Hello World!'
   >>>                 # Use Ctrl-D or Ctrl-Z to exit, or close window

2. Programs. Your code (i.e., module) file module1.py and the operating system shell interactions should look like this:

   print('Hello module world!')
   
   % python module1.py
   Hello module world!

   Again, feel free to run this other ways—by clicking the file’s icon, by using IDLE’s Run→Run Module menu option, and so on.

3. Modules. The following interaction listing illustrates running a module file by importing it:

   % python
   >>> import module1
   Hello module world!
   >>>

   Remember that you will need to reload the module to run it again without stopping and restarting the interpreter. The question about moving the file to a different directory and importing it again is a trick question: if Python generates a module1.pyc file in the original directory, it uses that when you import the module, even if the source code (.py) file has been moved to a directory not in Python’s search path. The .pyc file is written automatically if Python has access to the source file’s directory; it contains the compiled byte code version of a module. See Chapter 3 for more on ...