From: Siep Korteling <s.korteling@...>
Date: 2008-04-30T05:31:39+09:00
Subject: Re: Getting array index for non-zero elements

Rob Biedenharn wrote:
> On Apr 29, 2008, at 3:46 PM, Victor Reyes wrote:
> 
>>            [5,0,0,4,0,6,0,3,0],
>> # Output: 0 0 0 0 1 9 0 4 0
>>          puts
>> nonzeroIndex 
>>                                                           #
>> Output: *nil*
>>
>> Any help will be greatly appreciated, as usual!
>>
>> Thank you
>>
>> Victor
> 
> 
> 
> irb> require 'code/ruby/ext/enumerable.rb'
> => true
> irb> @ga[0]
> => [0, 0, 0, 0, 1, 9, 0, 4, 0]
> irb> @ga[0].map_with_index {|e,i| e.zero? ? nil : i}
> => [nil, nil, nil, nil, 4, 5, nil, 7, nil]
> irb> @ga[0].map_with_index {|e,i| e.zero? ? nil : i}.compact
> => [4, 5, 7]
> 
> Then you just need Enumerable#map_with_index
> 
> module Enumerable
>    # Like each_with_index, but the value is the array of block results.
>    def map_with_index
>      a = []
>      each_with_index { |e,i| a << yield(e, i) }
>      a
>    end
> end
> 
> -Rob
> 
> Rob Biedenharn    http://agileconsultingllc.com
> Rob@AgileConsultingLLC.com

It works without the 'require' here.(VERSION=1.8.6). I like the 
map_with_index method (new for me), but isn't it overkill here?

@ga.each do |sub_arr|
    sub_arr.each_with_index do |value,index|
       print index.to_s + " " unless value == 0
    end
    puts
end

Regards,

Siep
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