title: PHP str_replace replace spaces with underscores
body: <p>Is there a reason that I'm not seeing, why this doesn't work?</p>
  
  <pre><code>    $string = $someLongUserGeneratedString;
      $replaced = str_replace(' ', '_', $string);
      echo $replaced;
  </code></pre>
  
  <p>The output still includes spaces... Any ideas would be awesome</p>