From: Patrick Doyle <wpdster@...>
Date: 2008-08-18T22:56:34+09:00
Subject: Re: Hash#each vs Hash#each_pair

> p "p hash : #{hash}"
> p "hash.each"
> hash.each do |e| #e is [key,value]
>  p e
> end
I am just trying to understand why hash.each returns [key, value]
instead of value the way that array.each does:
#!/usr/bin/ruby

hash = {1 => 'one', 2 => 'two', 3 => 'three'}
array = ['one', 'two', 'three']

p "p hash : #{hash}"
p "hash.each"
hash.each do |e| #e is [key,value]
 p e
end

p "p array : #{array}"
p "array.each"
array.each do |e|
 p e
end

The answer might be "because that's the way it's always been done, and
there's no way we're going to change it because a newbie asked for it
to be changed!".  (The careful reader might notice that I haven't
asked for anything to be changed -- I'm simply trying to understand
the thinking that went into the decision to make Hash#each operate
differently than Array#each)

In my case, I have some code in which a bunch of data has been
collected into an array, and I would like to modify my code such that
the collection of data is stored in a Hash instead of an Array object.
 I had assumed that, since I used object.each everywhere that I
iterated through my data, it would be as simple as changing the code
where I stuff the values into the collection.  Obviously, my
assumption proved incorrect.  Which led me to the question, "Now, I
wonder why they did that?"  So I've asked the question.

--wpd