[Tutor] Problems with Importing into the Python Shell

[Mark Lawrence]

On 12/06/2010 05:50, Andrew Martin wrote:
> Hey, everyone, I am new to programming and just downloaded Python 2.6 onto
> my windows vista laptop. I am attempting to follow 4.11 of the tutorial
> called "How to Think Like a Computer Scientist: Learning with Python v2nd
> Edition documentation" (
> http://openbookproject.net/thinkcs/python/english2e/ch04.html). However, I
> am having some trouble. First off, I do not understand how to import things
> into the python shell. I have a script I saved as chap03.py, but when I try
> to import it into the python shell i get an error like this:
>
>>>> from chap03 import *

This is generally considered bad practice, I'll let you do some research 
to find out why. :)

>
> Traceback (most recent call last):
>    File "<pyshell#8>", line 1, in<module>
>      from chap03 import *
>    File "C:/Python26\chap03.py", line 2
>      print param param
>                      ^
> SyntaxError: invalid syntax
>>>>
>
> The chap03.py file is a simple one that looks like this:
> def print_twice(param):
>      print param param

One of the great advantages of Python is trying things from an 
interactive prompt, so let's go.

c:\Users\Mark\python>python
Python 2.6.5 (r265:79096, Mar 19 2010, 21:48:26) [MSC v.1500 32 bit 
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
 >>> def print_twice(param):
...     print param param
   File "<stdin>", line 2
     print param param
                     ^
SyntaxError: invalid syntax

So it is!  What's print_twice trying to do, let's guess?

 >>> def print_twice(param):
...     print param, param
...
 >>> print_twice('Hi Andrew')
Hi Andrew Hi Andrew
 >>>

Better!  See how I slotted that comma into the function print_twice, 
just hope my guess is right.  So run up some editor/IDE and slap that 
comma in there, it should at least keep you going.

>
> My second problem is that I need to install and import GASP in order to
> follow the tutorial. When I tried to do import it, I ran into an error like
> this:
>>>> from gasp import *
>
> Traceback (most recent call last):
The line above basically says "start reading from the bottom up"
>    File "<pyshell#9>", line 1, in<module>
>      from gasp import *
>    File "C:\Python26\lib\site-packages\gasp\__init__.py", line 1, in<module>
>      from api import *
>    File "C:\Python26\lib\site-packages\gasp\api.py", line 1, in<module>
>      import backend
>    File "C:\Python26\lib\site-packages\gasp\backend.py", line 7, in<module>
>      except ImportError: raise 'Pygame is not installed. Please install it.'
> TypeError: exceptions must be old-style classes or derived from
> BaseException, not str
The TypeError means exactly what it says.  The ImportError is trying to 
raise an exception, but what follows is a string type, not an exception 
type.  Just install Pygame to get yourself going, at some point in the 
tutorial you're bound to run into exception handling.
>>>>
>
> Can anybody help me with this?
>
> Thanks a lot
>
> P.S. SORRY FOR THE LONG EMAIL

By some standards this doesn't even qualify as short, it's just a snippet.

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HTH, and keep asking as Python lists are renowned for their friendlyness.

Mark Lawrence.