Python Pandas – 从DateTimeIndex中提取每年的序数日（ordinal day）并设置特定的时间序列频率

要从DatetimeIndex中提取符合特定时间序列频率条件下的每年的序数日，可以使用 DateTimeIndex.dayofyear 属性。

首先，导入必要的库 −

import pandas as pd

创建一个周期为6，以 D（天）为频率的 DatetimeIndex −

datetimeindex = pd.date_range('2021-10-20 02:30:50', periods=6, tz='Australia/Sydney', freq='D')

显示DateTimeIndex −

print("DateTimeIndex...\n", datetimeindex)

获取每年的序数日 −

print("\n获取每年的序数日...\n",datetimeindex.dayofyear)

示例

下面是代码 −

import pandas as pd

# DatetimeIndex with period 6 and frequency as D i.e. day
# The timezone is Australia/Sydney
datetimeindex = pd.date_range('2021-10-20 02:30:50', periods=6, tz='Australia/Sydney', freq='D')

# display DateTimeIndex
print("DateTimeIndex...\n", datetimeindex)

# display DateTimeIndex frequency
print("DateTimeIndex frequency...\n", datetimeindex.freq)

# get the day of year
print("\n获取每年的序数日...\n",datetimeindex.dayofyear)

输出

输出如下所示 −

DateTimeIndex...
DatetimeIndex(['2021-10-20 02:30:50+11:00', '2021-10-21 02:30:50+11:00',
'2021-10-22 02:30:50+11:00', '2021-10-23 02:30:50+11:00',
'2021-10-24 02:30:50+11:00', '2021-10-25 02:30:50+11:00'],
dtype='datetime64[ns, Australia/Sydney]', freq='D')
DateTimeIndex frequency...
<Day>

获取每年的序数日...
Int64Index([293, 294, 295, 296, 297, 298], dtype='int64')