From: Mike Austin <noone@...>
Date: 2006-03-14T08:53:45+09:00
Subject: Re: array element access

dblack@wobblini.net wrote:
> Hi --
> 
> On Tue, 14 Mar 2006, Mike Austin wrote:
> 
>> Tomas Fischer wrote:
>>> Hi,
>>>
>>> I've got an array a= [1,2,3,4,5,6] and want to access each second 
>>> element:
>>> b=[2,4,6]. How is this done in ruby?
>>>
>>> I know, that I can use a for-loob and modulo operator, but I think 
>>> there is a "ruby way" of doing this.
>>>
>>> Thanks.
>>> tomas
>>
>> I've always been intrigued by creating a generalized enumeration 
>> system. Have you guys seen this: 
>> http://www.rubyweeklynews.org/20050710 : accessing index inside map.  
>> For example:
>>
>> (1..10).collect.with_index { |v, i| v * i }
>>
>> I think that is sweet!  I wonder if it can be generalized enough to do 
>> this:
>>
>> file.collect.each_byte.with_index { |b, i| b + 1 }
> 
> I'm not sure why, but to my eye this has always looked somewhat
> obscure.  I guess it's something about having to read to the right,
> even to the extent of not seeing a block, before I know what's being
> returned (array vs. enumerator).  It's almost as if the call to
> collect wasn't a "real" call to collect, but rather a kind of
> place-holder for a collect operation.  I'm not sure.

Ok, what if you rearrange the order of the calls:

file.each_byte.with_index.collect { |b, i| b + 1 }

That's more left-to-right object-oriented sounding.  Come to think of it I like 
this better because now collect is at the end, and that is the the final intent 
(with the block being next to it).

Mike