title: Regular expression to remove anything but alphanumeric & spaces (in PHP)
body: <p>I'm trying to remove, via regular expression, all but alphanumeric characters &amp; spaces. </p>
  
  <p>Here's the conversion I am hoping to achieve.</p>
  
  <pre><code>"I am a string" → "I am a string"
  "How are you?" → "How are you"
  "#53-Jeff" → "53-Jeff"
  </code></pre>
  
  <p>So far I have this:</p>
  
  <pre><code>return preg_replace("/[^0-9a-zA-Z]/","", $val);
  </code></pre>
  
  <p>But being a regex novice, I can't figure out how to insert a space. I had odd results when I tried.</p>