[GLLUG] The Python talk reminds me of a question...

[Ashton Shortridge]

Hello,

I've been coding in C for a decade now, and, while I'm not particularly 
skilled, I am able to hack out stuff that I need fairly quickly.

However, times change and I have decided to learn Python. I've skimmed the 
tutorial and other information sources, but to really get into it I figured 
the best approach was to decide on a little project and implement it with 
Python.

My project is to implement a bibliography program - basically a little 
database with journal articles, book chapters, etc, that I can ultimately 
toss.

My first approach is purposefully not object-oriented. A few lines of code is 
sufficient to import the records from a text file (very cool that it's so 
easy - would have taken much more effort in C!). I am using a list (really a 
list of lists), which is probably not the best, or possibly even a good, way 
to do it. The structure looks something like this:

db = [['Smith', 'Jane C', '', '', 'Great ponies of Ohio'],['Xie', 'Fang', '', 
'', 'Mane Coloration']]

In the example above there are two records. Each record has 5 'fields', 
including two that are empty (for a second author, if any).

I would like to be able to do something with the records based on the title 
field - item 4 in each of the records. I can return this for the second 
record using the following syntax:

db[1][4]
will return 'Mane coloration'

Here comes the question. I want to return ALL of the titles. Intuitively (but 
wrongly), I tried:
db[:][4]
which returns an error that basically says there is no 4th element in the list 
- meaning the list called db, which only contains two things. Other stabs 
also met with failure.

So, the question is, how can I refer to the nth elements of ALL records? If 
the answer is: "hey silly, use a different data structure!" , then just tell 
me about that structure. And if there's a web reference about it (I've looked 
over the official Python documentation with some care and a lot of 
confusion), I'd appreciate learning that too.

The next step by the way will be to create some sort of record object and 
build version II of the application. While both will be open source, don't 
look for it in your distro any time soon!

Thanks,

Ashton

-- 
Ashton Shortridge
Assistant Professor			ashton at msu.edu
Dept of Geography			http://www.msu.edu/~ashton
Michigan State University		(517) 432-3561