title: Numpy split with percentage on a matrix
body: <p>I have issues to understand the following coding and I am new to python:</p>
  
  <pre><code>data_a, data_b, data_C = np.split(original_data.sample(frac=1, random_state=1729), 
                                 [int(0.7 * len(original_data)), int(0.9*len(original_data))])
  </code></pre>
  
  <p>so my original data set has a complete of 38000 rows. After this split method the <code>data_a</code> has 26600 rows. Now <code>data_b</code> has 7600 rows, <code>data_c</code> has 3800 rows. So I do get that 70% of original_data will be 26600 rows. But why does <code>data_b</code> has 7600 rows and <code>data_c</code> 3800. I read the documentation about that split method and from what I understand the coding I would have suggested that for the rest of 30% data from my initial 38000 rows, 90% will split into <code>data_b</code> that would be 10260 rows. Not 7600 rows.</p>