[Tutor] implementing a table data structure in python?

[Maarten]

Hello tutors,

As i'm new to this mailing list so i shall introduce myself. My name is 
Maarten and except for some shell scripting I have little practical 
experience in programming (I'm a Linux/Solaris sys-admin). I've doing 
(mostly) reading about Python. But now trying, despite of my lack of 
talent for programming, to do write some stuff in Python (i don't call 
them programs yet;).

So maybe a bit bold for a newbie to start posting a correction but i 
wanted the code to work:

Kent Johnson wrote:
<snip>
> columns = [1,3,4]  # Column numbers to show, 0-based
> 
> f = open('mydata.txt')
> for line in f:
>     data = line.split()  # Assuming your data is tab- or space-delimited
>     data = [ item for i, item in data if i in columns ]  # Filter out unwanted columns
>     print data  # Output one row of text - put your formatting here
> 
> There are probably more efficient ways to extract the data but this 
> should get you started.

guess Kent forgot one line after:

     data = line.split()

adding next line after it:

     data = enumerate(data)

makes it work for me.

Assuming:
$ cat mydata.txt
1   1   2   3   23  0.1
13  2   3   4   24  0.15
24  1   1   2   12  0.2
45  2   3   5   1   0.12
116 6   2   7   27  0.18
211 9   4   6   28  0.45

Please correct my correction if i'm wrong.

Still got a question. This notation/syntax of the list:

[ item for i, item in data if i in columns ]

is quite new for me. Can someone point me to more examples of this use 
Or give me the name of it (it must have a name) so i can google it?

thx
Maarten