title: Can I remove a part of a string/text with elasticsearch?
body: <p>I have a big doubt about Elasticsearch and it's functions</p>
  <p>I have a field called requestparam which contatins info like this:</p>
  <p>?q=%22art%C3%ADculo%201915%22&amp;pagina=1&amp;indice=tesis&amp;extractos=120&amp;filtros=un
  defined&amp;size=10</p>
  <p>It's a query string, and I want to know if there's a way to query or to split a string like in this example:</p>
  <p>?q=%22art%C3%ADculo%201915%22</p>
  <p>So whenever it founds the substring &quot;&amp;pagina&quot; it removes the rest of the string.
  Is that possible with Elasticsearch?</p>