title: Using ifelse to remove unwanted rows from the dataset in R
body: <p>I have a dataset where I want to remove the occurences of month 11 in the first observation year for a couple of my individuals. Is it possible to do this with ifelse? Something like:  </p>
  
  <pre><code>ifelse(ID=="1" &amp; Month=="11" and Year=="2006", "remove these rows",  
    ifelse(ID=="2" &amp; Month=="11" &amp; Year=="2007", "remove these rows",   
           "nothing"))  
  </code></pre>
  
  <p>As always, all help appreciated! :)</p>