title: split Dataset to N size datesets by Date?
body: <p>Seems like a trivial question but I couldn't find the answer online.</p>
  
  <p>I have a dataset of 1259 observation by 7 variables.
  One of the variables is Date and I want to split the dataset to small datasets of size 50*7 that will keep in order the dates.</p>
  
  <p>I've tried to to this and got the right size of dataset but the dates were messed up.</p>
  
  <pre><code>split(data, sample(1:50), nrow(data),replace = T)
  </code></pre>