title: preg_replace to remove stand-alone numbers
body: <p>I'm looking to replace all standalone numbers from a string where the number has no adjacent characters (including dashes), example:</p>
  
  <blockquote>
    <p>Test 3 string 49Test 49test9 9</p>
  </blockquote>
  
  <p>Should return Test string 49Test 49Test9</p>
  
  <p>So far I've been playing around with:</p>
  
  <pre><code>   $str = 'Test 3 string 49Test 49test9 9';
     $str= preg_replace('/[^a-z\-]+(\d+)[^a-z\-]+?/isU', ' ', $str);
     echo $str;
  </code></pre>
  
  <p>However with no luck, this returns</p>
  
  <blockquote>
    <p>Test string 9Test 9test9</p>
  </blockquote>
  
  <p>leaving out part of the string, i thought to add [0-9] to the matches, but to no avail, what am I missing, seems so simple?</p>
  
  <p>Thanks in advance</p>