From: Stefano Mioli <stefano.mioli@...>
Date: 2011-07-16T04:01:41+09:00
Subject: Re: Comparing hashes based on their keys

On 7/15/11 7:18 PM, Rob Biedenharn wrote:

class Hash
   def same_key_structure?(other)
     return false unless other.is_a?(Hash)
     return false unless self.keys == other.keys && 
self.keys.all?{|_|_.is_a?(Symbol)}
     self.keys.all? {|_|self[_].is_a?(Hash) ? 
self[_].same_key_structure?(other[_]) : !other[_].is_a?(Hash)}
   end
end


Now that I think about it, that

	self.keys == other.keys

might cause problems, because I didn't specify (sorry, my bad) that I 
don't care about which order the keys appear in.

In other words, I consider these two hashes to be equal:

	h1 = {:x => nil, :y => nil}
	h2 = {:y => nil, :x => nil}

but h1.keys == h2.keys would return false in this context.

Array could probably benefit from something like RSpec's '=~' to test 
arrays for equality regardless of the order of their elements, wouldn't it?
That is, unless I'm missing some existing method that does that.

-- 
Stefano Mioli