From: Daniel Carrera <dcarrera@...>
Date: 2003-01-29T02:46:22+09:00
Subject: Re: Use mulit-dim. Arrays? [Questions from a Ruby Newbie (file io and d ata structures)...]


Thank you for posting that script.  I learned a fair bit from it.
I'll keep it for my own use.

Ruby rocks.


On Wed, Jan 29, 2003 at 01:41:55AM +0900, ahoward wrote:

> #!/usr/bin/env ruby
> 
> class Cfg < Array
> 
>   DEFAULT_DELIM = ','
>   DEFAULT_COMMENT = '#'
> 
>   attr_reader :max_cols
>   attr_accessor :comment
>   attr_accessor :delim
> 
>   def initialize path, delim = DEFAULT_DELIM, comment = DEFAULT_COMMENT
>     @max_cols = 0
>     @delim = delim
>     @comment = comment
>     comment_pat = %r{#{comment}.*$}
>     lines = IO.readlines path
> 
>     lines.each do |line|
>       line.strip!
>       next if line.size == 0
>       line[comment_pat] = ''
>       row = line.split delim
>       next unless row.size > 0
>       @max_cols = [row.size, @max_cols].max
>       self << row
>     end
>   end
> 
>   def to_s
>     (map {|r| r.join (delim)}).join ($/) << $/
>   end
> 
>   def pad value = nil
>     map! {|r| r.fill value, r.size...max_cols}
>   end
> end
> 
> 
> if $0 == __FILE__
>   csv = Cfg.new 'in.csv'
>   print csv
>   csv.pad '!'
>   print csv
> 
>   printers = Cfg.new 'printers.txt', "\t"
>   print printers
> end
> 
> 
> the program outputs this :
> 
> /usr/home/howardat/eg/ruby > ./Csv.rb
> 
> col1,col2,col3
> a,b,c
> d,e,f
> g,h
> j
> col1,col2,col3
> a,b,c
> d,e,f
> g,h ,!
> j,!,!
> hp  bugs
> xerox fg-color
> 
> 
> my point is simply that, although you can do things really tersely and slickly
> in ruby (as you can in perl) i think it's ability to use OO programming for
> every day tasks is where it really shines.  if you wrote a class similar to
> the one above, and made it recognize which type of config file it was reading
> based on file extension (for example), and saved this class into your
> site_ruby/ directory, all your scripts which require cfg information start
> looking really short and sweet, something like :
> 
>   require 'cfg.rb'
> 
>   cfgpath = ARGV.shift
> 
>   cfg = Cfg.new cfgpath
> 
>   cfg.each do |row|
>     ... do something
>   end
> 
> which is exactly what i've done at our site.
> 
> just thought i'd point all that out since, IMHO, it's the OO aspect of ruby
> which is the most usefull, and yet also the aspect which requires the biggest
> paradigm shift.
> 
> -a
> 
> 
> -- 
> 
>  ====================================
>  | Ara Howard
>  | NOAA Forecast Systems Laboratory
>  | Information and Technology Services
>  | Data Systems Group
>  | R/FST 325 Broadway
>  | Boulder, CO 80305-3328
>  | Email: ahoward@fsl.noaa.gov
>  | Phone:  303-497-7238
>  | Fax:    303-497-7259
>  ====================================
> 
> 

-- 
Daniel Carrera
Graduate Teaching Assistant.  Math Dept.
University of Maryland.  (301) 405-5137