title: preg_match only letters, spaces and dashes and spaces allowed
body: <p>i know that one condition that im currently using where it gives an error if $stringabc contains anything but numbers is :</p>
  
  <pre><code>if(preg_match("/[^0-9]/",$stringabc))
  </code></pre>
  
  <p>I want an if condition where it gives an error if $stringdef contains anything but letters, spaces and dashes (-).</p>