# Pastebin pN9Ezear
@HCLarsen @Willamin about mapping hash etc. there's no need to create another hash. Simply change values or add new key and delete old key...

hsh = {"foo" => "bar", "baz" => "qux"}
iterator = hsh.each_key

key = iterator.next
hsh[key.to_s] = "dfgh"
hsh["newKey"] = "new"
hsh.delete(key.to_s)

key = iterator.next
hsh[key.to_s] = "1234"

hsh.each do |key, value|
  puts key
  puts value
end

gives:

baz
1234
newKey
new

Sorry, i am on my phone. You can do anything equivalent :)