title: Regex allow dot and comma
body: <p>I have got this expression: </p>
  
  <pre><code>^(?!0*(\.0+)?$)(\d+|\d*\.\d+)$
  </code></pre>
  
  <p>and it works fine except that I would like it to accept a comma as a separator as well. With this pattern, <code>1,5</code> or <code>,123</code> is false. It should be true.</p>
  
  <p>Specifically,</p>
  
  <pre><code>0 = false
  0.0 = false
  null = false
  . = false
  , = false
  0.123 = true
  0,123 = true
  .123 = true
  ,123 = true
  123.123 = true
  123,123 = true
  </code></pre>