array.rb

[:aa, :bb, :cc].map(&:to_s) #=> ["aa", "bb", "cc"]
{:aa => 'aa', :bb => 'bb'}.map(&:to_s) #=> ["aaaa", "bbbb"] 
ary = {:aa => 'aa', :bb => 'bb'}.map do |key, value|
  [key.to_s, value]
end
Hash[ary] #=> {"bb"=>"bb", "aa"=>"aa"}