title: Numpy/pandas error when printing a dataframe
body: <p>I'm getting the following error when I try to print a dataframe or try to drop the columns. I have uninstalled and reinstalled the latest version of numpy.</p>
  <pre><code>
    File &quot;C:\Users\IDALAB HCM - II\Desktop\Shreyas\model histories\history_2017_50k_upsampled\semeval_2017_50k_upsampled.py&quot;, line 75, in &lt;module&gt;
      print(data9)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\core\frame.py&quot;, line 687, in __repr__
      show_dimensions=show_dimensions,
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\core\frame.py&quot;, line 820, in to_string
      return formatter.to_string(buf=buf, encoding=encoding)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\io\formats\format.py&quot;, line 916, in to_string
      return self.get_result(buf=buf, encoding=encoding)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\io\formats\format.py&quot;, line 523, in get_result
      self.write_result(buf=f)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\io\formats\format.py&quot;, line 835, in write_result
      max_len = Series(lines).str.len().max()
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\core\generic.py&quot;, line 11217, in stat_func
      f, name, axis=axis, skipna=skipna, numeric_only=numeric_only
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\core\series.py&quot;, line 3891, in _reduce
      return op(delegate, skipna=skipna, **kwds)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\core\nanops.py&quot;, line 125, in f
      result = alt(values, axis=axis, skipna=skipna, **kwds)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\pandas\core\nanops.py&quot;, line 837, in reduction
      result = getattr(values, meth)(axis)
  
    File &quot;C:\Users\IDALAB HCM - II\.conda\envs\keras-gpu\lib\site-packages\numpy\core\_methods.py&quot;, line 39, in _amax
      return umr_maximum(a, axis, None, out, keepdims, initial, where)
  
  TypeError: int() argument must be a string, a bytes-like object or a number, not '_NoValueType'
  </code></pre>