BUG: Timestamp rounding wrong implementation fixed #11963

[Tux1]

closes #11963

[jreback]

pls reuse the existing code rather than repeating, e.g. something like:

def _round(self, freq, rounder):
        from pandas.tseries.frequencies import to_offset
         unit = to_offset(freq).nanos

         if getattr(self,'tz',None) is not None:
             values = self.tz_localize(None).asi8
         else:
             values = self.asi8
          result = (unit*rounder(values/unit)).astype('i8')
          attribs = self._get_attributes_dict()
          if 'freq' in attribs:
              result = result.tz_localize(self.tz)
          return result

def round(self, freq):
    return self._round(freq, np.round)

def floor(self, freq):
    return self._round(freq, np.floor)

furtther use an Appender on the doc-string to avoid repeating

[jreback]

pls update Timedelta as well. need impl and tests.

[Tux1]

@jreback please note the warning I add in the round documentation about rounding of float. The behaviour is slightly different than the arithmetical definition but it refers to Numpy implementation

[jreback]

looks good.

small comments. pls run git diff master | flake8 --diff and incorporate pep8 fixes.

[jreback]

ping on green.

[Tux1]

I think it's okay

[jreback]

merged via 4437e9c