title: insert row in data frame without creating new columns with R
body: <p>I have this :</p>
  
  <pre><code>    1  2  3
  1  10 11 12
  2  13 14 15
  3  16 17 18
  4  19 20 21
  5  22 23 24
  </code></pre>
  
  <p>And I want this :</p>
  
  <pre><code>    1     2  3
  1  10    11 12 
  2  13    14 15
  3   0  0.00  
  4  16    17 18
  5  19    20 21
  6  22    23 24
  </code></pre>
  
  <p>Can anyone tell me how to do that ?
  I tried rbind, rbind.fill, smartbind, but the result is not what I expect for.</p>
  
  <p>Thank you</p>