title: Create sparse matrix from tweets
body: <p>I have some tweets and other variables that I would like to convert into a sparse matrix.</p>
  
  <p>This is basically what my data looks like. Right now it is saved in a data.table with one column that contains the tweet and one column that contains the score. </p>
  
  <pre><code>Tweet               Score
  Sample Tweet :)        1
  Different Tweet        0
  </code></pre>
  
  <p>I would like to convert this into a matrix that looks like this:</p>
  
  <pre><code>Score Sample Tweet Different :)
      1      1     1         0  1
      0      0     1         1  0
  </code></pre>
  
  <p>Where there is one row in the sparse matrix for each row in my data.table. Is there an easy way to do this in R?</p>