---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-16-9050e29ead3a> in <module>()
      1 data = dataset[dataset.sma=='SE']
      2 time = data.st_time
----> 3 dates.date2num(time[data.active==0].values)

/Library/Python/2.7/site-packages/matplotlib-1.4.x-py2.7-macosx-10.8-intel.egg/matplotlib/dates.pyc in date2num(d)
    292         if not d.size:
    293             return d
--> 294         return _to_ordinalf_np_vectorized(d)
    295 
    296 

/Library/Python/2.7/site-packages/numpy-1.8.0.dev_b307a8a_20130729-py2.7-macosx-10.8-intel.egg/numpy/lib/function_base.pyc in __call__(self, *args, **kwargs)
   1896             vargs.extend([kwargs[_n] for _n in names])
   1897 
-> 1898         return self._vectorize_call(func=func, args=vargs)
   1899 
   1900     def _get_ufunc_and_otypes(self, func, args):

/Library/Python/2.7/site-packages/numpy-1.8.0.dev_b307a8a_20130729-py2.7-macosx-10.8-intel.egg/numpy/lib/function_base.pyc in _vectorize_call(self, func, args)
   1956             _res = func()
   1957         else:
-> 1958             ufunc, otypes = self._get_ufunc_and_otypes(func=func, args=args)
   1959 
   1960             # Convert args to object arrays first

/Library/Python/2.7/site-packages/numpy-1.8.0.dev_b307a8a_20130729-py2.7-macosx-10.8-intel.egg/numpy/lib/function_base.pyc in _get_ufunc_and_otypes(self, func, args)
   1920             # arrays (the input values are not checked to ensure this)
   1921             inputs = [asarray(_a).flat[0] for _a in args]
-> 1922             outputs = func(*inputs)
   1923 
   1924             # Performance note: profiling indicates that -- for simple functions

/Library/Python/2.7/site-packages/matplotlib-1.4.x-py2.7-macosx-10.8-intel.egg/matplotlib/dates.pyc in _to_ordinalf(dt)
    195             dt -= delta
    196 
--> 197     base = float(dt.toordinal())
    198     if hasattr(dt, 'hour'):
    199         base += (dt.hour / HOURS_PER_DAY + dt.minute / MINUTES_PER_DAY +

AttributeError: 'numpy.datetime64' object has no attribute 'toordinal'

In[18: time[:4]
Out[18]:
95    2010-04-12 07:23:12
96    2010-06-10 20:43:07
100   2010-06-21 06:37:28
221   2009-07-20 06:53:38
Name: st_time, dtype: datetime64[ns]