Even better than has_key?, is has_key_and_value?

gistfile1.rb

class Hash

  # if key doesn't exist, returns false
  # if self[key] == false, returns false
  # if self[key] == nil, empty, or blank, returns false
  # if self[key] exists and self[key] == true, or evaluates to true, returns true
  def has_key_and_value? (key)
    return false unless has_key?(key)
    return false if self[key].nil?
    return false if self[key].respond_to?(:empty?) && self[key].empty?
    return false if self[key].respond_to?(:blank) && self[key].blank?
    self[key]
  end

end