如何添加delta到python datetime.time？ [英] How to add delta to python datetime.time?

问题描述

From：

http://docs.python.org/py3k/library/datetime.html#timedelta-objects

timedelta对象表示持续时间，两个
日期或时间之间的差异。

A timedelta object represents a duration, the difference between two dates or times.

所以为什么我会收到错误：

So why i get error with this:

>>> from datetime import datetime, timedelta, time
>>> datetime.now() + timedelta(hours=12)
datetime.datetime(2012, 9, 17, 6, 24, 9, 635862)
>>> datetime.now().date() + timedelta(hours=12)
datetime.date(2012, 9, 16)

>>> datetime.now().time() + timedelta(hours=12)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unsupported operand type(s) for +: 'datetime.time' and 'datetime.timedelta'

推荐答案

datetime.time 对象不支持添加 datetime.timedelta s。

datetime.time objects do not support addition with datetime.timedeltas.

虽然有一种自然的定义，但是时钟算术。
您可以这样计算：

There is one natural definition though, clock arithmetic. You could compute it like this:

import datetime as dt
now = dt.datetime.now()
delta = dt.timedelta(hours = 12)
t = now.time()
print(t)
# 12:39:11.039864

print((dt.datetime.combine(dt.date(1,1,1),t) + delta).time())
# 00:39:11.039864

dt.datetime.combine（...）提升datetime.time t 到 datetime.datetime 对象，然后添加增量，并将结果下降回 datetime.time 对象。

dt.datetime.combine(...) lifts the datetime.time t to a datetime.datetime object, the delta is then added, and the result is dropped back down to a datetime.time object.

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