title: Removal of rows containing zero
body: <p>I have a dataset of variables</p>
  
  <pre><code>Year    Age Bag Computer
  2008    0   4   4
  2008    1   5   3
  2008    2   5   12.5
  2008    3   5   15
  2008    4   5   33
  2008    5   5   11
  2008    85  5   3.5
  2008    .   .   .
  2008    108 0   0
  2008    109 0   0
  2008    110+    0   0
  </code></pre>
  
  <p>I need to subset this in R in order to remove all the zero on my database and get this final table</p>
  
  <pre><code>Year    Age Bag Computer
  2008    0   4   4
  2008    1   5   3
  2008    2   5   12.5
  2008    3   5   15
  2008    4   5   33
  2008    5   5   11
  2008    7   5   14.5
  2008    8   5       17
  </code></pre>
  
  <p>without zero for the older ages.</p>