title: Hash to convert month to number
body: <p>I am using hash to convert month into number.</p>
  
  <pre><code>%mon2num = qw(
      jan 1  feb 2  mar 3  apr 4  may 5  jun 6
      jul 7  aug 8  sep 9  oct 10 nov 11 dec 12
  );
  </code></pre>
  
  <p>Here i want to make all month jan, feb..dec case insensitive.Let me know how to do.</p>