Class YearLocator

lib/matplotlib/dates.py:1449–1496

Make ticks on a given day of each year that is a multiple of base. Examples:: # Tick every year on Jan 1st locator = YearLocator() # Tick every 5 years on July 4th locator = YearLocator(5, month=7, day=4)

class YearLocator(RRuleLocator):
    """
    Make ticks on a given day of each year that is a multiple of base.

    Examples::

      # Tick every year on Jan 1st
      locator = YearLocator()

      # Tick every 5 years on July 4th
      locator = YearLocator(5, month=7, day=4)
    """
    def __init__(self, base=1, month=1, day=1, tz=None):
        """
        Parameters
        ----------
        base : int, default: 1
            Mark ticks every *base* years.
        month : int, default: 1
            The month on which to place the ticks, starting from 1. Default is
            January.
        day : int, default: 1
            The day on which to place the ticks.
        tz : str or `~datetime.tzinfo`, default: :rc:`timezone`
            Ticks timezone. If a string, *tz* is passed to `dateutil.tz`.
        """
        rule = rrulewrapper(YEARLY, interval=base, bymonth=month,
                            bymonthday=day, **self.hms0d)
        super().__init__(rule, tz=tz)
        self.base = ticker._Edge_integer(base, 0)

    def _create_rrule(self, vmin, vmax):
        # 'start' needs to be a multiple of the interval to create ticks on
        # interval multiples when the tick frequency is YEARLY
        ymin = max(self.base.le(vmin.year) * self.base.step, 1)
        ymax = min(self.base.ge(vmax.year) * self.base.step, 9999)

        c = self.rule._construct
        replace = {'year': ymin,
                   'month': c.get('bymonth', 1),
                   'day': c.get('bymonthday', 1),
                   'hour': 0, 'minute': 0, 'second': 0}

        start = vmin.replace(**replace)
        stop = start.replace(year=ymax)
        self.rule.set(dtstart=start, until=stop)

        return start, stop


class MonthLocator(RRuleLocator):