title: Get rid of rows with duplicate attributes in R
body: <p>I have a big dataframe with columns such as:</p>
  
  <pre><code>ID, time, OS, IP
  </code></pre>
  
  <p>Each row of that dataframe corresponds to one entry. Within that dataframe for some <b>IDs</b> several entries (rows) exist. I would like to get rid of those multiple rows (obviously the other attributes will differ for the same ID). Or put different: I only want one single entry (row) for each ID.</p>
  
  <p>When I use <code>unique</code> on the ID column, I only receive the levels (or each unique ID), but I want to keep the other attributes as well.
  I have tried to use <code>apply(x,2,unique(data$ID))</code>, but this does not work either.</p>