title: Binding columns with similar column names in the same dataframe in R
body: <p>I have a data frame that looks somewhat like this: </p>
  
  <pre><code>df &lt;- data.frame(0:2, 1:3, 2:4, 5:7, 6:8, 2:4, 0:2, 1:3, 2:4)
  colnames(df) &lt;- rep(c('a', 'b', 'c'), 3)
  &gt; df
    a b c a b c a b c
  1 0 1 2 5 6 2 0 1 2
  2 1 2 3 6 7 3 1 2 3
  3 2 3 4 7 8 4 2 3 4
  </code></pre>
  
  <p>There are multiple columns that have the same name.  I would like to rearrange the data frame so that the columns with the same names combine into their own supercolumn, so that there are only unique column names left, for example:</p>
  
  <pre><code>&gt; df
    a b c
  1 0 1 2
  2 1 2 3
  3 2 3 4
  4 5 6 2
  5 6 7 3
  6 7 8 4
  7 0 1 2
  8 1 2 3
  9 2 3 4
  </code></pre>
  
  <p>Any thoughts on how to do this?  Thanks in advance!</p>