From: Dimitri Aivaliotis <aglarond@...>
Date: 2006-04-07T00:04:44+09:00
Subject: Re: Basic input/output question

Hi Peter,

On 4/6/06, Peter Bailey <pbailey@bna.com> wrote:
> Hello,
> I spent my $40 on "Programming Ruby," but, it seems dedicated to C
> programmer rocket scientists. I work in publishing and basically I just
> need to open files, convert the data, and write the files, either to the
> same file or to another. Can someone please help me to write a simple
> structure to read a file "text1.txt", do regexes and stuff in it to
> convert data, and then write the output to "text2.txt."

A very general way to do this is:

big = 10485760 # we'll deal with files larger than 10MB specially

read = "text1.txt" # the file to be read

write = "text2.txt" # the file to be written

File.open( write, "w") do |w|
  File.open( read ) do |r|
    if File.size( read ) < big
      while line = r.gets
	# do somethin with line
        w << line
      end
    else# read the file in big-sized chunks
      while !f.eof?
        f.read( big ).split($/).each do |line|
          # do somethin with line	
          w << line
        end
      end
    end
  end
end

- Dimitri