From: Phil Rhoades <phil@...>
Date: 2008-01-11T01:18:59+09:00
Subject: Re: Multiline (block) CSV file processing

James,


On Fri, 2008-01-11 at 00:12 +0900, James Gray wrote:
> On Jan 10, 2008, at 7:47 AM, Phil Rhoades wrote:
> 
> > I am looking for suggestions for Ruby utilities (and gems?) for a
> > flexible, easy method of processing multi-line blocks of CSV text eg  
> > in
> > a CSV file, lines 1-5 are the first block and lines 6-10 are the  
> > second
> > block etc.  Then for each block I want to:
> >
> > - print the first field of line 1
> > - second field of line 2
> > - fifth field of line 3
> > - tenth field of line 4
> > - twelfth field of line 5
> >
> > as fields of a new line.
> 
> Well, if I fully understand the request, I would use code like the  
> following with the fastercsv gem:
> 
> #!/usr/bin/env ruby -wKU
> 
> require "rubygems"
> require "faster_csv"
> 
> input  = FCSV.open(ARGV.shift)
> output = FCSV.open("filtered.csv", "w")
> 
> catch(:out_of_lines) do
>    loop do
>      lines  =  Array.new(5) { input.shift or throw :out_of_lines }
>      output << lines.zip([0, 1, 4, 9, 11]).map { |line, i| line[i] }
>    end
> end
> 
> __END__
> 
> Hope that helps.


Thanks but not quite - say my input file is:

1 2 3 4 5 6 7 8 9 a b c
11 12 13 14 15 16 17 18 19 d e f
21 22 23 24 25 26 27 28 29 g h i
31 32 33 34 35 36 37 38 39 j k l
41 42 43 44 45 46 47 48 49 m n o

The output should be:

1 12 25 j o

Regards,

Phil.
-- 
Philip Rhoades

Pricom Pty Limited  (ACN 003 252 275  ABN 91 003 252 275)
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