ch275 101 [easy].rb

def valid_element(element_name, proposed_symbol)
  #not parsing as is not required
  #checking size
  return false if proposed_symbol.size != 2
  proposed_symbol.downcase!
  element_name.downcase!

  #checking both letters are present
  return false unless element_name.include?(proposed_symbol[0]) # && element_name.include?(proposed_symbol[1])

  #checking order
  rest_of_name = element_name.split('').drop_while {|c| c != proposed_symbol[0]} . drop(1)
  return false unless rest_of_name.include?(proposed_symbol[1])
  true
end

def test_run
  test_elements = [ 'Spenglerium, Ee',
  'Zeddemorium, Zr',
  'Venkmine, Kn',
  'Stantzon, Zt',
  'Melintzum, Nn',
  'Tullium, Ty']

  test_elements.each{|s| puts valid_element( s.split(', ').first, s.split(', ').last)}
  nil
end