title: Regex for enforcing a string contains English letters AND numbers
body: <p>I am trying to create a regular expression for accepting strings of 8 characters composed of both letters and numbers, and not only letters or numbers.</p>
  
  <p>The regex <code>'^[A-Z0-9]{8}$'</code> is not enough as it allows words like <code>'ABCDEFGH'</code> or <code>'12345678'</code>. How do I create a regex to only accept 8 character strings containing both capital letters AND numbers like <code>'AB123C7Q'</code>?</p>