From: ahoward <ahoward@...>
Date: 2003-06-17T12:40:35+09:00
Subject: Re: Extracting columns from Array withSubstitution problem

On Tue, 17 Jun 2003, Qubert wrote:

> I have a little hurdle to jump on this code.  I am manipulating a lot of
> data that is in a columnar format.  The first row has the titles of each
> column that I successfully use to call the columns through the command line
> (ARGV.shift).  Below I show 2 attempts to pull out the columns of data using
> the reference to the first row.  The first one (y1) works, until I found
> that absent data was marked by one or more *.  So y1 was changing *** to 0,
> but I need to input these missing data points as -9.  So y2 was attempted,
> in which it finds the ** but then for some reason inputs the entire array x
> at the end of the newly collected array.  Now I didn't believe that it would
> work, but I didn't expect it to input array x either.  So I would like some
> help creating code that will collect a new array like y1 but substitute -9
> for ***.

> Partial code:
> arg1 = ARGV.shift
> arg2 = ARGV.shift
> label = Array.new  # for y1, y2 I found I didn't need to declare y1=Array.new?
> label = x.shift   # first line is headers for the columns
> y1 = x.collect {|j| j[label.index(arg1)].to_i}  # works but changes ** into 0
> y2 = x.each do |j|    # doesn't work, inputs all of x as y2, i.e. y2 = x
> � if /\*+/ =~ j[label.index(arg2)]
> ��� -9
>   else
>     j[label.index(arg2)].to_i
> � end
> end


* reverse the args to '=~'

eg.

  if /\*+/ =~ j[label.index(arg2)]

becomes

  if j[label.index(arg2)] =~ /\*+/



> Thank you for the help, Ruby is great, I just haven't found the "Way".

me neither - i just keep searching.  ;-)

btw.  i do stuff like this all the time and made a *tiny* little module which
helps.  although some may argue my stuff is crap, the RAA is great - using it
is the ruby way!

  #!/usr/bin/env ruby

  #http://raa.ruby-lang.org/list.rhtml?name=array-fields
  require 'arrayfields'

  rows = DATA.readlines.map{|row| row.split}
  fields = rows.shift
  rows.fields = fields

  p rows[0]['DIR']	  # "030"
  p rows[0]['DIR', 'CLG'] # ["030", "722"]

  __END__
  DIR SPD GUS CLG
  030   6 *** 722
  360   5 *** 722
  020   * *** 722
  030   6 *** 722

-a
--
  ====================================
  | Ara Howard
  | NOAA Forecast Systems Laboratory
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  | Data Systems Group
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  | ~ > ruby -e 'p(%.\x2d\x29..intern)'
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