[Tutor] Parsing Question

[Alan Gauld]

"Michael Morrissey" <gdoghomes at gmail.com> wrote

> a text file that looks like this:
> 1 the 126 name
> 2 of 127 very
>
> Each has 2 numbers and 2 words on it. Each number is related to the word
> that comes after it. So "1" and "the" are connected (kinda like a
> dictionary), and "126" and "name" are related.
>
> Using the above text file as an input, I'm trying to make an output that
> lists all the words, one word per line, but none of the numbers. I was
> hoping to get the words listed in order of their related numbers. So, the
>
> I can open and loop over the text, I'm just not sure what commands I 
> should
> use to parse each line. Can anyone give me suggestions or examples?

For this a simple split() command should give you a list of 4 items.

I suggest you store each pair in a tuple (num, word) and put the
tuples in a list.

You can then sort the list and the tuples will be in numeric order
(element 0).

Then iterate over the list printing the word (element 1 of the tuple)

In pseudo code:

words = []
for line in open(fname):
      four = line.split()
      words.append( (four[0],four[1]) )
      words.append( (four[2],four[3]) )

for word in sorted(words):
    print word[1]

You should probably be able to do the first for loop as a list
comprehension,  but I can't think of how to get the split() call
embedded into it right now!

HTH,

-- 
Alan Gauld
Author of the Learn to Program web site
http://www.alan-g.me.uk/