title: How to validate number in perl?
body: <p>I know that there is a library that do that</p>
  
  <blockquote>
    <p>use Scalar::Util qw(looks_like_number);</p>
  </blockquote>
  
  <p>yet I want to do it using perl regular expression. And I want it to work for double numbers not for only integers.</p>
  
  <p>so I want something better than this</p>
  
  <blockquote>
    <p>$var =~ /^[+-]?\d+$/</p>
  </blockquote>
  
  <p>thanks.</p>