title: regex. how to exclude a substring from the result after it matches the pattern
body: <p>I wonder how i can exclude a substring from the result after it matches the pattern.
  example:</p>
  
  <pre><code>&lt;a href="?page1"&gt;&lt;?php __('string1');?&gt;&lt;/a&gt;
  &lt;a href="?page2"&gt;&lt;?php __("string2");?&gt;&lt;/a&gt;
  </code></pre>
  
  <p>I want to get only the strings passed as parameters to the __() function. i tried this regex:</p>
  
  <pre><code>'/__\(((\'([^\']+)\')|(\"([^\"]+)\"))/'
  </code></pre>
  
  <p>but that returns 'string1' and "string2" wrapped in single quotes and double quotations.<br>
  how can i exclude single quotes and double quotations?</p>