title: dataframe values.tolist() datatype
body: <p>I have a dataframe like this:</p>
  
  <p><a href="https://i.stack.imgur.com/rJVf7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rJVf7.png" alt="enter image description here"></a></p>
  
  <p>This dataframe has several columns. Two are of type <code>float</code>: <code>price</code> and <code>change</code>, while <code>volme</code> and <code>amount</code>are of type <code>int</code>.
  I use the method <code>df.values.tolist()</code> change df to list and get the data:</p>
  
  <pre><code>datatmp = df.values.tolist()
  print(datatmp[0])
  
  [20160108150023.0, 11.12, -0.01, 4268.0, 4746460.0, 2.0]
  </code></pre>
  
  <p>The <code>int</code> types in <code>df</code> all change to <code>float</code> types.
  My question is why do <code>int</code> types change to the <code>float</code> types? How can I get the <code>int</code> data I want?</p>