title: read txt file with different number of columns
body: <p>How can I read in R, numerous txt files with different number of columns? 
  e.g 
  I have the following data: </p>
  
  <pre><code>6 4 2 
  5 5 3
  3 3 4 5 6 
  4 5 6 7 8
  6 3 2 5 8 4 3 
  1 4 5 0 5 4 8 
  </code></pre>
  
  <p>Thanks </p>