使用遞迴規則放置日期刻度

iCalendar RFC 指定了定義日期序列的遞迴規則 (rrules)。您可以在 Matplotlib 中使用 rrules 來放置日期刻度。

此範例會在每個第 5 個復活節設定自訂日期刻度。

請參閱 https://dateutil.readthedocs.io/en/stable/rrule.html 以取得 rrules 的說明。

import datetime

import matplotlib.pyplot as plt
import numpy as np

from matplotlib.dates import (YEARLY, DateFormatter, RRuleLocator, drange,
                              rrulewrapper)

# Fixing random state for reproducibility
np.random.seed(19680801)


# tick every 5th easter
rule = rrulewrapper(YEARLY, byeaster=1, interval=5)
loc = RRuleLocator(rule)
formatter = DateFormatter('%m/%d/%y')
date1 = datetime.date(1952, 1, 1)
date2 = datetime.date(2004, 4, 12)
delta = datetime.timedelta(days=100)

dates = drange(date1, date2, delta)
s = np.random.rand(len(dates))  # make up some random y values


fig, ax = plt.subplots()
plt.plot(dates, s, 'o')
ax.xaxis.set_major_locator(loc)
ax.xaxis.set_major_formatter(formatter)
ax.xaxis.set_tick_params(rotation=30, labelsize=10)

plt.show()