Pandas 美国大选日的假期日历规则

Question

在使用 Pandas 假期 class 创建假期日历时，我无法确定为美国选举日创建日历的正确规则。美国选举日被定义为 11 月第一个星期一之后的星期二，每偶数年出现一次。使用假期 class 定义：

class USElectionCalendar(AbstractHolidayCalendar):
"""        
Federal Presidential  and Congressional election day.
Tuesday following the first Monday, 2 to 8 November every two even numbered years.
Election Days can only occur from November 2nd through 8th inclusive.
"""

rules = [
    Holiday("Election Day",month=11, day=2, offset=pd.DateOffset(weekday=TU(1))),
]

和

start_date = '20160108'
end_date   = '20261231'

进入功能

def holidays_between_dates(calendar, start_date, end_date):

    cal = calendar
    dates = cal.holidays(start_date, end_date, return_name=True)

    return dates

returns

2016-11-08    Election Day
2017-11-07    Election Day
2018-11-06    Election Day
2019-11-05    Election Day
2020-11-03    Election Day
2021-11-02    Election Day
2022-11-08    Election Day
2023-11-07    Election Day
2024-11-05    Election Day
2025-11-04    Election Day
2026-11-03    Election Day

除了奇数年，一切都很好。我已经尝试合并两个偏移量，如 issue 中所讨论的那样。向规则添加 2 年的偏移量

Holiday("Election Day", month=11, day=2, offset=[ pd.DateOffset(weekday=TU(1)), pd.DateOffset(years=2) ])

只是将第一次出现的时间移到未来 2 年。我不确定所需的时间序列是否可行。那么问题来了：

是否可以直接构建这个日历，或者我是否需要使用第二个函数从 Pandas 日历对象中删除奇数年？

Answer 1

您可以在制定假期时使用遵守而不是抵消，并在奇数年return None:

def election_observance(dt):
    if dt.year % 2 == 1:
        return None
    else:
        return dt + pd.DateOffset(weekday=TU(1))


class USElectionCalendar(AbstractHolidayCalendar):
    """
    Federal Presidential  and Congressional election day.
    Tuesday following the first Monday, 2 to 8 November every two even numbered years.
    Election Days can only occur from November 2nd through 8th inclusive.
    """

    rules = [
        Holiday('Election Day', month=11, day=2, observance=election_observance)
    ]


cal = USElectionCalendar()

start_date = '20160108'
end_date = '20261231'

print cal.holidays(start_date, end_date, return_name=True)

输出：

2016-11-08    Election Day
2018-11-06    Election Day
2020-11-03    Election Day
2022-11-08    Election Day
2024-11-05    Election Day
2026-11-03    Election Day
dtype: object

请注意，您不想在构造假日时同时使用偏移量和观察值，并且尝试这样做会在更新的 pandas 版本中引发异常。

Pandas 美国大选日的假期日历规则

Pandas Holiday Calendar Rule for US Election day

python

calendar

pandas