From: "David A. Black" <dblack@...>
Date: 2007-10-25T04:57:50+09:00
Subject: Re: .each do |foo, bar|     what does bar do?

Hi --

On Thu, 25 Oct 2007, Thufir wrote:

> "code_words.each do |real, code|
> idea.gsub!( real, code )
> end
> You see the each method? The each method is all over in Ruby. It's
> available for Arrays, Hashes, even Strings. Here, our code_words
> dictionary is kept in a Hash. This each method will hurry through all
> the pairs of the Hash, one dangerous word matched with its code word,
> handing each pair to the gsub! method for the actual replacement."
>
> from page 33 of whys-poignant-guide-to-ruby.pdf
>
>
>
> Is this similar to nested for statements?  I don't think so.  In the
> first line, why are both "real" and "code" part of the interation?
>> From my understanding of a hash, you can iterate through the keys only
> and then find the corresponding bit of the hash.
>
> Why would this fail:
>
> code_words.each do |real|
> idea.gsub!( real, code )
> end
>
> wouldn't the corresponding code get looked up by during the loop?  Or,
> how could the above be changed so that it would work?

Hashes yield key,value pairs to #each. So you need two block params to
pick them up.

If you just want the keys, you can use #each_key.


David

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