>>> import pandas as pd >>> pd.__version__ u'0.19.0rc1' >>> pd.Series([pd.np.nan]).round() Warning (from warnings module): File "C:\Program Files\Python27\lib\site-packages\pandas\core\series.py", line 1340 result = _values_from_object(self).round(decimals) RuntimeWarning: invalid value encountered in rint 0 NaN dtype: float64