title: "AttributeError: 'DataFrame' object has no attribute 'dtype'" using pandas to_datetime
body: <p>I have been using <strong>Python 2.7.13</strong> on a windows machine to write my code.  But I am now trying to run my code on a Unix cluster using Python <strong>2.7.12-goolf-2015a</strong>. When I run my code on the cluster with 2.7.12, I encounter an error in the pandas function <code>to_datetime</code> which does not occur using 2.7.13.</p>
  <p>The error occurs when I try to convert a date entries in a dataframe to datetime.</p>
  <pre class="lang-py prettyprint-override"><code>df = pd.DataFrame({'year': [2015, 2016],
                         'month': [2, 3],
                         'day': [4, 5]})
  pd.to_datetime(df)
  </code></pre>
  <p>Here is an example ot the error I get with the <code>to_datetime</code> command</p>
  <pre><code>Traceback (most recent call last):
  File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
  File &quot;/usr/local/easybuild/software/Python/2.7.12-goolf-
  2015a/lib/python2.7/site-packages/pandas-0.16.1-py2.7-linux-
  x86_64.egg/pandas/tseries/tools.py&quot;, line 343, in to_datetime
  return _convert_listlike(arg, box, format)
  File &quot;/usr/local/easybuild/software/Python/2.7.12-goolf-
  2015a/lib/python2.7/site-packages/pandas-0.16.1-py2.7-linux-
  x86_64.egg/pandas/tseries/tools.py&quot;, line 266, in _convert_listlike
  if com.is_datetime64_ns_dtype(arg):
  File &quot;/usr/local/easybuild/software/Python/2.7.12-goolf-
  2015a/lib/python2.7/site-packages/pandas-0.16.1-py2.7-linux-
  x86_64.egg/pandas/core/common.py&quot;, line 2513, in is_datetime64_ns_dtype
  tipo = _get_dtype(arr_or_dtype)
  File &quot;/usr/local/easybuild/software/Python/2.7.12-goolf-
  2015a/lib/python2.7/site-packages/pandas-0.16.1-py2.7-linux-
  x86_64.egg/pandas/core/common.py&quot;, line 2458, in _get_dtype
  return arr_or_dtype.dtype
  File &quot;/usr/local/easybuild/software/Python/2.7.12-goolf-
  2015a/lib/python2.7/site-packages/pandas-0.16.1-py2.7-linux-
  x86_64.egg/pandas/core/generic.py&quot;, line 2083, in __getattr__
  (type(self).__name__, name))
  AttributeError: 'DataFrame' object has no attribute 'dtype'
  </code></pre>
  <p>The to_datetime works when I load Python/3.5.2-intel-2016.u3, but that causes other problems. I am inexperienced with Unix operating systems and as I don’t have admin rights to software on the cluster, I am pretty tied to using 2.7.12</p>