title: Use regular expression to fetch 3 groups from string
body: <p>This is my expected result.</p>
  
  <p>Input a string and get three returned string.</p>
  
  <p>I have no idea how to finish it with Regex in Ruby.</p>
  
  <p>this is my roughly  idea.</p>
  
  <pre><code>match(/(.*?)(_)(.*?)(\d+)/)
  </code></pre>
  
  <h1>Input and expected output</h1>
  
  <pre><code># "R224_OO2003" =&gt; R224, OO, 2003
  # "R2241_OOP2003" =&gt; R2244, OOP, 2003
  </code></pre>