def shift_backward(self, numPeriods): if self.periodicity == SECONDS: self.startDT = dt_subtract_seconds(self.startDT, numPeriods) self.endDT = dt_subtract_seconds(self.endDT, numPeriods) elif self.periodicity == MONTHS: self.startDT = dt_subtract_months(self.startDT, numPeriods) self.endDT = dt_subtract_months(self.endDT, numPeriods) elif self.periodicity == QUARTERS: self.startDT = dt_subtract_months(self.startDT, 3*numPeriods) self.endDT = dt_subtract_months(self.endDT, 3*numPeriods) elif self.periodicity == YEARS: self.startDT = dt_subtract_months(self.startDT, 12*numPeriods) self.endDT = dt_subtract_months(self.endDT, 12*numPeriods) else: raise NotImplementedError
def truncate_end(self, numPeriods): if self.periodicity == SECONDS: self.endDT = dt_subtract_seconds(self.endDT, numPeriods) elif self.periodicity == MONTHS: self.endDT = dt_subtract_months(self.endDT, numPeriods) elif self.periodicity == QUARTERS: self.endDT = dt_subtract_months(self.endDT, 3*numPeriods) elif self.periodicity == YEARS: self.endDT = dt_subtract_months(self.endDT, 12*numPeriods) else: raise NotImplementedError