title: How to reshape multiple rows to a single row with several columns
body: <p>This may seem an obvious questions for someone who has practice with <code>reshape</code> package but I'm trying to get use to its functions and I can't figure out the right syntax!</p>
  
  <p>Let's have the following data frame,</p>
  
  <pre><code>df &lt;- data.frame(matrix(1:12,ncol=3),row.names=letters[1:4])
  
    X1 X2 X3
  a  1  5  9
  b  2  6 10
  c  3  7 11
  d  4  8 12
  </code></pre>
  
  <p>how can we bind the rows into columns in order to get the following result?</p>
  
  <pre><code>  X1.a X2.a X3.a X1.b X2.b X3.b X1.c X2.c X3.c X1.d X2.d X3.d
       1    5    9    2    6   10    3    7   11    4    8   12
  </code></pre>
  
  <p>Thank you</p>