title: How to update values with dplyr
body: <p>I'm currently trying to update values from a data.frame using dplyr butI don't know if it is possible to replace a subset of values?</p>
  
  <pre><code># the net4 table
  head(net4)
  Source: local data frame [6 x 4]
  
    temps2 NNET NET ave
  1     18    2   4  36
  2     18    2   4  36
  3     22    2   4  44
  4     18    2   4  36
  5     22    2   4  44
  6     27    3   4  36
  
  # I would like to do the same command line as below:
  subs &lt;- (net4$ave &lt; 10 &amp; net4$ave!=net4$temps2)
  net4$ave[subs] &lt;- with(net4[subs,], temps2/NNET*NET)
  </code></pre>
  
  <p>Thanks</p>