From: James Edward Gray II <james@...>
Date: 2006-11-27T00:40:10+09:00
Subject: Re: find index of first non zeo value in array

On Nov 26, 2006, at 8:54 AM, Olivier wrote:

> Le dimanche 26 novembre 2006 15:00, Josselin a �crit :
>> with :
>> array = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21, 0, 0, 0, 0,
>> 0, 0, 0, 0, 0, 0]
>>
>> I wrote :
>> array.index(array.detect {|x| x > 0})    => 15
>>
>> is there a better and simpler way to do it ?
>> thanks
>>
>> joss
>
> In that case, it is simpler to use an external counter, i think :
>
> c = 0
> array.each{|v| break if not v.zero?; c += 1}
> puts c # => 15

You can ask Ruby to maintain the counter, if you want:

 >> require "enumerator"
=> true
 >> array = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21, 0, 0,  
0, 0,
?> 0, 0, 0, 0, 0, 0]
=> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 21, 0, 0, 0, 0, 0,  
0, 0, 0, 0, 0]
 >> result = array.enum_with_index.find { |n, i| n.nonzero? }.last  
rescue nil
=> 15
 >> array.slice!(15, 1)
=> [21]
 >> array
=> [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  
0, 0, 0]
 >> result = array.enum_with_index.find { |n, i| n.nonzero? }.last  
rescue nil
=> nil

James Edward Gray II