From: Brian Adkins <lojicdotcom@...>
Date: 2008-01-11T03:45:11+09:00
Subject: Re: Multiline (block) CSV file processing

On Jan 10, 11:18 am, Phil Rhoades <p...@pricom.com.au> wrote:
> 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

File.open("data.txt", "r") do |file|
  i = 0
  file.each_line do |line|
    print line.chomp.split[[1, 2, 5, 10, 12][i]-1] + ' '
    puts '' if (i = (i + 1) % 5) == 0
  end
end

Or, the following might be more fun:

def each_block file
  while !file.eof
    result = []
    5.times { result << file.readline.chomp }
    yield result
  end
rescue
end

File.open("data.txt", "r") do |file|
  each_block(file) do |block|
    [1, 2, 5, 10, 12].zip(block).each do |field, line|
      print line.split[field-1] + ' '
    end
    puts ''
  end
end

Brian Adkins