From: Ola Bini <ola.bini@...>
Date: 2006-09-12T16:54:18+09:00
Subject: Re: newbie: yaml array of arrays

allan.m.miller@gmail.com wrote:
> Hello,
> 
> I'm new to yaml, and yaml in Ruby.
> 
> I'm trying to create a yaml file in a text editor, one part of which
> will consist of an array of of arrays.  The data structure I'm trying
> to represent is:
> 
> [['a', 'b', 'c'], ['d', 'e', 'f'], ['g', 'h', 'i']]
> 
> an array of three arrays.
> 
> I've tried to create this yaml file in a text editor (test.cfg):
> 
> -- a
>  - b
>  - c
> -- d
>  - e
>  - f
> -- g
>  - h
>  - i
> 
> and read it in as follows
> 
> require 'yaml'
> na = open('test.cfg') { |f| YAML.load(f) }
> 
> I get a load error:
> 
> $ ./test.rb
> /usr/lib/ruby/1.8/yaml.rb:119:in `load': parse error on line 9, col -1:
> `' (ArgumentError)
>         from /usr/lib/ruby/1.8/yaml.rb:119:in `load'
>         from ./test.rb:3
>         from ./test.rb:3:in `open'
>         from ./test.rb:3
> 
> The last line seems o be causing an ArgumentError.
> 
> I'm sure my approach is completely off - how does one represent an
> array of arrays in yaml, and load it into a Ruby array of arrays?
> 
> Thanks.
> 
> 
> 

Hi,

This approach should work without trouble. Do this:

puts [%w(a b c), %w(d e f), %w(g h i)].to_yaml

your output should be
---
- - a
   - b
   - c
- - d
   - e
   - f
- - g
   - h
   - i

Another way is to use the flow-style like this:
---
- [a, b, c]
- {d, e, f]
- [g, h, i]

-- 
  Ola Bini (http://ola-bini.blogspot.com)
  JvYAML, RbYAML, JRuby and Jatha contributor
  System Developer, Karolinska Institutet (http://www.ki.se)
  OLogix Consulting (http://www.ologix.com)

  "Yields falsehood when quined" yields falsehood when quined.