From: William James <w_a_x_man@...>
Date: 2009-02-08T06:05:22+09:00
Subject: Re: cannot remove multiple spaces

Tom Cloyd 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
> 
>   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
> 
>   open( "h2t-out.txt", "w" ) { |f| f.write( data ) }
> 
> end
> 
> %w(rubygems ruby-debug readline strscan logger fileutils).each{ |lib| 
> require lib }
> 
> main
> 
> === input file ===
> 
> <h1>Library    catalog  listing           </h1>x
> 
> <h3>Library    catalog  listing           </h3>x
> 
> <h2>Library    catalog  listing           </h2>x
> 
> p(subtitle).   A    complete listing of all material in the Library
> 
> 
> === output file ===
> 
> 
> h1. Library    catalog  listing           x
> 
> h3. Library    catalog  listing           x
> 
> h2. Library    catalog  listing           x
> 
> p(subtitle).   A    complete listing of all material in the Library
> 
> ==============
> 
> The "x"s in the input file are to show that while the end tags are
> being removed the space before them is NOT.
> 
> t.

puts IO.readlines("data2").map{|line|
  line.sub( /<(h\d)>/, '\1. ' ).sub( /<\/h\d>/, "").
  squeeze " " }

--- output ---

h1. Library catalog listing x

h3. Library catalog listing x

h2. Library catalog listing x

p(subtitle). A complete listing of all material in the Library