From: David Alan Black <dblack@...>
Date: 2002-05-06T11:46:32+09:00
Subject: Re: newbie Q: how to strip blank lines from file?

Hello --

On Mon, 6 May 2002, Stewart Midwinter wrote:

> Well, I've spent a few days reading about Ruby, and want to try my first
> project: a little utility that will read a file that has too many blank
> lines in it, and strip out all of those blank line (could contain spaces or
> tabs).
>
> As I tackles this, I realise that I need to have a good manual in front of
> me, because I'm not getting anywhere. I am definitely confused at this
> point, since this problem could be solved in one or two lines, I believe.
> Does anyone more experienced have any suggestions?  I looked in
> rubycookbook.org and couldn't find anything there either.
>
> Thanks!
>
> here's my attempt so far, which seems to go into an infinite loop.
>
> ---
> # IO.foreach("snip.txt") { |line| puts line }
> arr = IO.readlines("snip.txt")
> puts "I read in " + arr.length.to_s + "lines from file."
> def blank (s)    # looking for blank lines to chop
>    (s =~ /\S/) != nil
> end
> i = 0
> while i < arr.length do
>  if blank(arr[i]) == nil then arr[i] = nil
> IO.printf("snip.out")
> end
> # file.close("snip.out")
> end
> ---

You're working *much* too hard :-)  Try this:

  fout = File.open("snip.out", "w")
  File.open("snip.txt").each do |line|
    fout.print line if /\S/.match(line)
  end


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav