From: 7stud -- <bbxx789_05ss@...>
Date: 2008-03-02T14:39:47+09:00
Subject: Re: counting in for .. in ..

Gregory Seidman wrote:
> On Sun, Mar 02, 2008 at 07:24:34AM +0900, Daniel Liebig wrote:
>> i'm doing my first steps in ruby (on rails) and often use things like
>> 
>> for thing in @several_things
>>   print thing
>> end
> [...]
> 
> For reasons I find it difficult to express the for-in construct is 
> frowned
> upon. There are better and more flexible iteration constructs, and it 
> looks
> like you are starting to feel the need for them.
> 
>> But i often need a counter inside of the loop, may it be to create row
>> colors or other stuff. What i end up with then is:
>> 
>> i = 0
>> for thing in @several_things
>>   print thing + " No. " + i.to_s
>>   i += 1
>> end
> [...]
> 
> This is where each_with_index, one of those more flexible iteration
> constructs, comes in.
> 
> @several_thing.each_with_index do |thing,i|
>    print thing + " No. " + i.to_s
>    i += 1
> end
> 

Rather that should be:

arr = ['a', 'b', 'c']

arr.each_with_index do |elmt, i|
  puts "Element at index #{i} is: #{elmt}"
end

--output:--
Element at index 0 is: a
Element at index 1 is: b
Element at index 2 is: c
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