将日期时间向下舍入到前一小时

Question

如何将日期时间四舍五入到前一小时？ 例如：

print datetime.now().replace(microsecond=0)
>> 2017-01-11 13:26:12.0

向下舍入到前一小时：2017-01-11 12:00:00.0

Answer 1

如果你想四舍五入到小时，你可以简单地用零替换microsecond、second和minute：

print(datetime.now().replace(microsecond=0, second=0, minute=0))

---

如果要向下舍入到前一小时（如示例中所述 2017-01-11 13:26:12.0 到 2017-01-11 12:00:00.0 ），请将 microsecond 、 second 和 minute 替换为零，然后减去一小时：

from datetime import datetime, timedelta
print(datetime.now().replace(microsecond=0, second=0, minute=0) - timedelta(hours=1))

外壳中的示例：

$ python3
Python 3.5.2 (default, Nov 17 2016, 17:05:23) 
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from datetime import datetime, timedelta
>>> print(datetime.now().replace(microsecond=0, second=0, minute=0) - timedelta(hours=1))
2017-01-11 16:00:00

Answer 2

from datetime import datetime, timedelta
n = datetime.now() - timedelta(hours=1)
new_date = datetime(year=n.year, month=n.month, day=n.day, hour=n.hour)

Answer 3

from datetime import datetime
import pandas as pd
currTime = datetime.now()
floored = pd.to_datetime(currTime).floor('H').to_pydatetime()