def __rsub__()

in visualizeConnectData/lambdas/modifyCTR/isodate/duration.py [0:0]

• 35 lines of code
• 8 McCabe index (conditional complexity)

    def __rsub__(self, other):
        '''
        It is possible to subtract Duration objecs from date, datetime and
        timedelta objects.

        TODO: there is some weird behaviour in date - timedelta ...
              if timedelta has seconds or microseconds set, then
              date - timedelta != date + (-timedelta)
              for now we follow this behaviour to avoid surprises when mixing
              timedeltas with Durations, but in case this ever changes in
              the stdlib we can just do:
                return -self + other
              instead of all the current code
        '''
        if isinstance(other, timedelta):
            tmpdur = Duration()
            tmpdur.tdelta = other
            return tmpdur - self
        try:
            # check if other behaves like a date/datetime object
            # does it have year, month, day and replace?
            if (not(float(self.years).is_integer() and
                    float(self.months).is_integer())):
                raise ValueError('fractional years or months not supported'
                                 ' for date calculations')
            newmonth = other.month - self.months
            carry, newmonth = fquotmod(newmonth, 1, 13)
            newyear = other.year - self.years + carry
            maxdays = max_days_in_month(newyear, newmonth)
            if other.day > maxdays:
                newday = maxdays
            else:
                newday = other.day
            newdt = other.replace(year=newyear, month=newmonth, day=newday)
            return newdt - self.tdelta
        except AttributeError:
            # other probably was not compatible with data/datetime
            pass
        return NotImplemented