title: Add values to exsisting of a hash
body: <p>how can one insert additional values to an exsisting key of a hash in R.</p>
  
  <pre><code>h=hash()
  h[key1] = "value1"
  . ???
  h[key1] = exsisting values + "value2" = c(values(h),"value2")
  </code></pre>
  
  <p>??</p>