title: Having trouble keeping all variables after removing duplicates from a dataset
body: <p>So, I imported a dataset with 178 observations and 8 variables.  Then end goal was to eliminate all observations that were the same across three of those variables (2, 5, and 6).  This proved quite easy using the unique command.</p>
  
  <pre><code>mav2 &lt;- unique(mav[,c(2,5,6)])
  </code></pre>
  
  <p>The resulting <code>mav2</code> dataframe produced 55 observations, getting rid of all the duplicates!  Unfortunately, it also got rid of the other five variables that I did not use in the unique command (1,3,4,7, and 8).  I initially tried adding the two dataframes, of course this did not work since they were of unequal size.  I have also tried merging the two, but this fails and just gives the an output of the first dataset with all 178 observations.  </p>
  
  <p>The second dataset (<code>mav2</code>) did produce a new column (<code>row.names</code>) which is the row number for each observation from the initial dataset.</p>
  
  <p>If anyone could help me out on getting all 8 initial variables into a dataset with only the 55 unique observations, I would be very appreciative.  Thanks in advance.</p>