[BUG] DataFrame.describe fails if no numeric columns
DataFrame.describe function fails with the following when called on a 
Data Frame with no numeric columns: 

  /usr/lib64/python2.7/site-packages/pandas/core/ 
frame.py(2324)describe() 
   2322                        '25%', '50%', '75%', 'max'] 
   2323 
-> 2324         data = [tmp.count(), tmp.mean(), tmp.std(), tmp.min(), 
   2325                 tmp.quantile(.25), tmp.median(), 
   2326                 tmp.quantile(.75), tmp.max()] 
  /usr/lib64/python2.7/site-packages/pandas/core/frame.py(2361)count() 
   2359             frame = self 
   2360 
-> 2361         result = DataFrame.apply(frame, Series.count, 
axis=axis) 
   2362 
   2363         # what happens with empty DataFrame 
  /usr/lib64/python2.7/site-packages/pandas/core/frame.py(1984)apply() 
   1982         else: 
   1983             if not broadcast: 
-> 1984                 return self._apply_standard(func, axis) 
   1985             else: 
   1986                 return self._apply_broadcast(func, axis) 

> /usr/lib64/python2.7/site-packages/pandas/core/frame.py(2000)_apply_standar d() 

   1998             results[k] = func(target[k]) 
   1999 
-> 2000         if hasattr(results.values()[0], '**iter**'): 
   2001             result = self._constructor(data=results, 
index=target.index, 
   2002 
# 

The problem seems to be that in the function DataFrame.describe, tmp 
is empty if there are no numeric columns: 

cols = self._get_numeric_columns() 
tmp = self.reindex(columns=cols) 

Nonetheless, Series.describe itself works on non-numeric values.

 -- Marius 
