title: is there an r function for filtering ##NA## in a dataframe saved as a character
body: <p>I have the following data set whose character is ##NA##, that I want to filter</p>
  <pre><code>gps&lt;-c(&quot;##NA##&quot;,&quot; 36.8955044653751,-1.3190453373576&quot;,&quot;40.2380971776017,-0.423957630067816&quot;)
  cluster&lt;-c(147009,147009,147009)
  data1&lt;-data.frame(cluster,gps)
  data1
  </code></pre>
  <p>The expected output is</p>
  <pre><code>gps&lt;-c(&quot; 36.8955044653751,-1.3190453373576&quot;,&quot;40.2380971776017,-0.423957630067816&quot;)
      cluster&lt;-c(147009,147009)
      data2&lt;-data.frame(cluster,gps)
      data2
  </code></pre>