From: James Gray <james@...>
Date: 2008-09-02T21:13:32+09:00
Subject: Re: Parsing a CSV file column-wise


On Sep 2, 2008, at 3:59 AM, Chris Lowis wrote:

> 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]

Or you could access them by name:

#!/usr/bin/env ruby -wKU

require "rubygems"
require "faster_csv"

csv = FCSV.parse(<<END_DATA, :headers => true, :header_converters  
=> :symbol)
one,two,three
1,2,3
4,5,6
7,8,9
END_DATA
csv[:two]  # => ["2", "5", "8"]

__END__

James Edward Gray II