From: Chris Lowis <chris.lowis@...>
Date: 2008-09-02T17:59:39+09:00
Subject: Re: Parsing a CSV file column-wise

On Sep 2, 8:34 am, Lars Broecker <Lars.Broec...@iais.fraunhofer.de>
wrote:
> Chris Lowis schrieb:
>
>
>
> > Is there a short-cut to parsing a CSV file column-wise using any of
> > the available Ruby CSV libraries ?
>
> > For example, at the moment I have:
>
> >  require 'csv'
> >  data = "1,2,3\n4,5,6\n7,8,9"
> >  CSV::parse(data)   # => [["1", "2", "3"], ["4", "5", "6"], ["7", "8",
> > "9"]]
>
Lars,

That's great ! To summarise for anyone else looking for an answer :

Given a CSV file tmp.csv

   one,two,three
   1,2,3
   4,5,6
   7,8,9

Where the first row contains the column headers

  require 'fastercsv'
  table = FasterCSV::table('./tmp.csv')

  table.by_col[2] # => [3, 6, 9]


Thanks again,

Chris







> > But what I'd like is:
>
> >  CSV::parse(data,'columnwise')   # => [["1", "4", "7"], ["2", "5",
> > "8"], ["3", "6", "9"]]
>
> > Perhaps I just need to run the returned array through some kind of
> > transformation ?
>
> Take a look at FasterCSV. It is available via rubygems and allows
> different modes in which to work on the parsed csv including working on
> columns of csv files. Great library!
>
> HTH,
> Lars