From: Qubert <qubert@...>
Date: 2003-04-24T14:26:08+09:00
Subject: parsing large file into matrix

I work on a lot of flat files containing data with many columns
and thousands of rows.  I have recently started using ruby, in 
hopes to forgo the overworking of sed and awk or tedious coding of C.
So far I like it.

Question:  It would be ideal if I could open a file, read in the data 
and then start working on the resulting array by a [m,n] indexing.  Thus
far using Ruby I can do this fairly quickly:
x = File.open("file.txt").readlines
j = 0
ffsize = Array.new
name = Array.new
while j < x.length
  y = x[j].split('\t')
  ffsize[j] = y.shift.to_f/1024.0
  name[j] = y.shift
  j += 1
end

Currently I am just using a small dummy file as a test, but this will become
huge once I start using files with many columns of data and I will likely 
join these field arrays together again.
 
Is there a Ruby-way of creating an m by n array from the beginning?
I know the following doesn't work but something like it code would be nice:
x = File.open("file.txt").readlines.split('\t')

Then x would be an m by n array of m different data types.

Thanks,
Qubert