Question

Here is a ruby hash:

a = {
  :testOne => 1,
  :testTwo => 2
} 

How can I rename the keys so that they are underscored?

a = {
  :test_one => 1,
  :test_two => 2
}

Ken Bloom got me on the right tract here. You do need ActiveSupport or Rails3. You don’t need any specific gems for this solution however:

hash = Hash[a.map {|k,v| [k.to_s.underscore.to_sym, v]}]

Thanks ken!

Answer 1

Hash[a.map { |k,v| [k.to_s.downcase.sub('test','test_').to_sym, v] }]

Update: If you need to find the common root string, you can use this:

root = a.keys.inject do |m, e|
    s = m.to_s
    s.chop! while !e.to_s.start_with? s
    s
  end