From: Craig Demyanovich <cdemyanovich@...>
Date: 2009-02-07T23:21:27+09:00
Subject: Re: cannot remove multiple spaces

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See comments below.

On Sat, Feb 7, 2009 at 8:31 AM, Tom Cloyd <tomcloyd@comcast.net> wrote:

> I'm baffled by this strange outcome - I cannot reduce multiple spaces from
> a text file. This isn't just a regex problem, somehow. I'm failing to grasp
> something essential, but don't know what it is. All help appreciated, as
> usual!
>
> Here is a demo of my problem, in which I try two different ways, and both
> fail:
>
> === code ===
> # h2t.rb
>
> def main
>  # conversion table spec
>  conv = [
>  [ '<h1>', 'h1. ' ], [ '<h2>', 'h2. ' ], [ '<h3>', 'h3. ' ],
>  [ '<h4>', 'h4. ' ], [ '<h5>', 'h5. ' ], [ '<h6>', 'h6. ' ],  [ /<\/h\d>/,
> '' ],
>  [ " +", ' ' ]]  # <= this last array element should do the trick, but
> doesn't


The last element means replace occurrences of a space followed by a plus
with an empty string. I assume that you were trying to write a regular
expression, which would make your last array [/ +/, ''].

  data = open( 'h2t-in2.txt', 'r' ) { |f| ( f.readlines( data )).to_s  }
>
>  conv.each do |i|
>   data.gsub!( i[0], i[1] )
>  end
>  data.squeeze(' ')  # <= putting this here was sheer desperations, but even
> THIS fails


This does nothing because String#squeeze returns a new string that you don't
capture. Instead of using the array above, you could do

data = data.squeeze(' ')


>  open( "h2t-out.txt", "w" ) { |f| f.write( data ) }
>
> end
>
> %w(rubygems ruby-debug readline strscan logger fileutils).each{ |lib|
> require lib }
>
> main


Hope that helps.

Regards,
Craig

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