Where can I find an explanation of what the "=>" operator means in Ruby?
Let me give more detail. If you have this:
class Acct < ActiveRecord::Base
validates_confirmation_of :password, :email_address, :on => :create
end
What is the '=>' operator doing in this case? Thanks
The symbol "=>" is not an operator. It's just a syntactic means to express that there is a relationship of "key-value" between the other two elements. It's used to define hashes (or associative arrays, as they're called in some other languages, eg. PHP). In this sense, because "=>" it's not an operator, it doesn't do anything (so as symbols "[" and "]" don't do anything when used to define an array). If you are still confused, have a look into the Hash Ruby class and compare it to the Array class.
To expand on the accepted answer (it's not an operator), think of it basically in the same way as a comma.
{ "foo" => "bar", "a" => "b" }
The comma separates each pair in the hash, the => separates the key and the value inside the pair.