title: remove "()" in Rdata
body: <p>There is an example data.</p>
  <p>|type |
  |1,2()|
  |1,3()|
  |1    |</p>
  <p>I would like to remove &quot;()&quot; in the data.</p>
  <p>|type |
  |1,2  |
  |1,3  |
  |1    |</p>
  <p>So, I tried the &quot;str_replace&quot; in dplyr package.</p>
  <pre><code>mutate(type = str_replace(type, pattern=&quot;()&quot;, replacement =&quot;&quot;))
  </code></pre>
  <p>But it didn't work, and there is still &quot;()&quot; in the data.
  How does it work?</p>