From: Robert Klemme <bob.news@...>
Date: 2003-04-24T19:08:17+09:00
Subject: Re: parsing large file into matrix


"Brian Candler" <B.Candler@pobox.com> schrieb im Newsbeitrag
news:20030424085535.GA33201@uk.tiscali.com...
> On Thu, Apr 24, 2003 at 02:26:08PM +0900, Qubert wrote:
> > 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')
>
> x = File.open("file.txt").readlines.collect! do |line|
>         line.chomp.split("\t")
>     end
>
> Although that leaves the file open until garbage collection time. The
> following does not have that problem; it also processes the lines as
they
> are read.
>
> x = File.open("file.txt") do |f|
>   f.collect do |line|
>     line.chomp.split("\t")
>   end
> end

Thanks for correcting me.  That was what I intended.  What bugs me is that
documentation says that File.open() with a block returns nil.  But
apparently it works.  So with the additional conversion to float we get

matrix = File.open("file.txt") do |f|
  f.collect do |line|
    line.chomp.split("\t").map {|s|s.to_f}
  end
end

Cheers

    robert