title: Test if string could be boolean PHP
body: <p>I'm getting a string from a $_GET and I want to test if it could be a boolean, before I use it for a part of a mysql query. Is there a better way of doing it than:</p>
  
  <pre><code>function checkBool($string){
      $string = strtolower($string);
      if ($string == "true" || $string == "false" || 
          $string == "1" || $string == "0"){
          return true;
      }
      else {
          return false;
      }
  }
  
  if (checkBool($_GET['male'])){
      $result = mysql_query(
          "SELECT * FROM my_table " .
          "WHERE male='".$_GET['male']."'") or die(mysql_error());
  }
  </code></pre>