title: Replace in Array
body: <p>im trying make one replace in string from a array but this dont work</p>
  
  <pre><code>dna[i].replace('T', 'C');
  </code></pre>
  
  <p>and with this way work?</p>
  
  <pre><code>"ATCTA".replace('T', 'C');
  </code></pre>
  
  <p>why dont work with array, how i can use use a replace in array[]</p>
  
  <p>Now i have other problem, i want use various replaces in original string, how i can mahe this????</p>