="QUOTE">"[
      ]"</span> can be matched. This is using <span class="QUOTE">"0-9"</span> as a shorthand expression to mean any
      digit one through nine. It is the same as saying <span class="QUOTE">"0123456789"</span>. So any digit matches.
      The <span class="QUOTE">"+"</span> means one or more of the preceding expression must be included. The preceding
      expression here is what is in the square brackets -- in this case, any digit one through nine. Then, at the end,
      we have a grouping: <