title: Pandas: Sampling a DataFrame
body: <p>I'm trying to read a fairly large CSV file with Pandas and split it up into two random chunks, one of which being 10% of the data and the other being 90%.</p>
  
  <p>Here's my current attempt:</p>
  
  <pre><code>rows = data.index
  row_count = len(rows)
  random.shuffle(list(rows))
  
  data.reindex(rows)
  
  training_data = data[row_count // 10:]
  testing_data = data[:row_count // 10]
  </code></pre>
  
  <p>For some reason, <code>sklearn</code> throws this error when I try to use one of these resulting DataFrame objects inside of a SVM classifier:</p>
  
  <pre><code>IndexError: each subindex must be either a slice, an integer, Ellipsis, or newaxis
  </code></pre>
  
  <p>I think I'm doing it wrong. Is there a better way to do this?</p>