title: remove numbers and special characters from a string using php and regex
body: <p>I have some problems with removing numbers and special characters. I want to remove all numbers and special characters from the input. Here's my code :</p>
  
  <pre><code>$input = $_POST["input"];
  
  function preprocessing($input){
      $input = trim(strtolower($input));
      $remove = '/[^a-zA-Z0-9]/s';
      $result = preg_split($remove, $input, -1, PREG_SPLIT_NO_EMPTY);
      for($i = 0; $i &lt; count($resultl); $i++){
          $result[$i] = trim($result[$i]);
      }
      return $result;
  }
  </code></pre>
  
  <p>String example :
  qwd qwd qwdqd123 13#$%^&amp;*) ADDA ''''</p>
  
  <p>Output :
  Array ( [0] => qwd [1] => qwd [2] => qwdqd123 [3] => 13 [4] => adda ) </p>
  
  <p>The numbers still appear on my string. How to solve this ?
  Thank you before.</p>