title: Problems with "select" in R
body: <p>I use code:</p>
  <pre><code>z &lt;- filter(dat, Sex==&quot;M&quot; &amp; Diet==&quot;chow&quot;) %&gt;% select(Bodyweight) %&gt;% unlist.
  
  </code></pre>
  <p>And it is written:
  Error in select(., Bodyweight) : could not find function &quot;select&quot;</p>
  <p>Do you know how to fix it?
  This code was written by professors from Harvard.. Probably I have not installed the appropriate package..</p>