From: Josef 'Jupp' SCHUGT <jupp@...>
Date: 2003-10-13T04:46:47+09:00
Subject: Re: splitting a line by columns

Hi!

* Mike Campbell; 2003-10-12, 11:44 UTC:
> I have a line of text output in columnar form; what's the best way
> to split it into its requisite parts?

That's one of those 'it only takes n programmers to get n+1 results'
qestions. It strongly depends on what you mean by 'best way'.

> Say I have lines of
> 
> aaaaabbcccccddeee
> 
> I can do something like:
> 
> md = /(.....)(..)(.....)(..)(...)/.match(line);  # seems klugy somehow
> 
> Thoughts?

Here are mine:

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#!/usr/bin/env ruby

class Cutter < Array
  def cut(line)
    map { |range| line[range] }
  end
end

knife = Cutter.new([0..4, 5..6, 7..11, 12..13, 14..16])
md    = knife.cut(line)
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I am a bit surprised how powerful that ad hoc solution is: It
supports overlapping columns and columns can be arranged in arbitrary
order, ... The solution also makes it easy to programmatically select
the columns of interest before cutting anything:

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knife = Cutter.new()
knife.push(0..4)    if rand < 0.5
knife.push(5..6)    if rand < 0.5
knife.push(7..11)   if rand < 0.5
knife.push(12..13)  if rand < 0.5
knife.push(14..16)  if rand < 0.5
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Comments?

Please take notice of signature! / Bitte Signature beachten!

Josef 'Jupp' Schugt
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