title: str_replace() with associative array
body: <p>You can use arrays with str_replace():</p>
  
  <pre><code>$array_from = array ('from1', 'from2'); 
  $array_to = array ('to1', 'to2');
  
  $text = str_replace ($array_from, $array_to, $text);
  </code></pre>
  
  <p>But what if you have associative array?</p>
  
  <pre><code>$array_from_to = array (
   'from1' =&gt; 'to1';
   'from2' =&gt; 'to2';
  );
  </code></pre>
  
  <p>How can you use it with str_replace()?<br>
  Speed matters - array is big enough.</p>