title: Get continent name from country name in R
body: <p>I have a data frame with one column representing country names. My goal is to add one more column which gives the continent information. Please check the following use case:</p>
  
  <pre><code>my.df &lt;- data.frame(country = c("Afghanistan","Algeria"))
  </code></pre>
  
  <p>Is there a package that I can use to append a column of data containing the continent names without having the original data?    </p>