title: change many word in content by wordpress filter
body: <p>I using <code>wordpress</code> filter to change many word in content by this code bellow</p>
  
  <pre><code>function upperworld ($content){
  
      $string1 = array('1' =&gt; 'BA YEU CON', '2' =&gt; 'CON YEU ME' );
      $string = array('1' =&gt; 'abc', '2' =&gt; 'ccb' );
  
      foreach ($string as $key =&gt; $thay) {
          foreach ($string1 as $key =&gt; $canthay) {
              $content = str_replace($thay, $canthay, $content)
          }
      }
      return $content;
  }
  add_filter( 'the_content', 'upperworld' );
  </code></pre>
  
  <p>It not working, please help me to fix it</p>