如何将日期时间增加一天？
如何增加一个日期时间中的天数？
for i in range(1, 35)
date = datetime.datetime(2003, 8, i)
print(date)
但是我需要正确地跨越月份和年份，这有什么好办法吗？
8 个回答
16
目前所有的回答在某些情况下都是错误的，因为它们没有考虑到时区相对于协调世界时（UTC）的偏移会发生变化。所以在某些情况下，加上24小时和加上一整天的日历是不同的。
建议的解决方案
下面的解决方案适用于萨摩亚，并且保持当地时间不变。
def add_day(today):
"""
Add a day to the current day.
This takes care of historic offset changes and DST.
Parameters
----------
today : timezone-aware datetime object
Returns
-------
tomorrow : timezone-aware datetime object
"""
today_utc = today.astimezone(datetime.timezone.utc)
tz = today.tzinfo
tomorrow_utc = today_utc + datetime.timedelta(days=1)
tomorrow_utc_tz = tomorrow_utc.astimezone(tz)
tomorrow_utc_tz = tomorrow_utc_tz.replace(hour=today.hour,
minute=today.minute,
second=today.second)
return tomorrow_utc_tz
测试过的代码
# core modules
import datetime
# 3rd party modules
import pytz
# add_day methods
def add_day(today):
"""
Add a day to the current day.
This takes care of historic offset changes and DST.
Parameters
----------
today : timezone-aware datetime object
Returns
-------
tomorrow : timezone-aware datetime object
"""
today_utc = today.astimezone(datetime.timezone.utc)
tz = today.tzinfo
tomorrow_utc = today_utc + datetime.timedelta(days=1)
tomorrow_utc_tz = tomorrow_utc.astimezone(tz)
tomorrow_utc_tz = tomorrow_utc_tz.replace(hour=today.hour,
minute=today.minute,
second=today.second)
return tomorrow_utc_tz
def add_day_datetime_timedelta_conversion(today):
# Correct for Samoa, but dst shift
today_utc = today.astimezone(datetime.timezone.utc)
tz = today.tzinfo
tomorrow_utc = today_utc + datetime.timedelta(days=1)
tomorrow_utc_tz = tomorrow_utc.astimezone(tz)
return tomorrow_utc_tz
def add_day_dateutil_relativedelta(today):
# WRONG!
from dateutil.relativedelta import relativedelta
return today + relativedelta(days=1)
def add_day_datetime_timedelta(today):
# WRONG!
return today + datetime.timedelta(days=1)
# Test cases
def test_samoa(add_day):
"""
Test if add_day properly increases the calendar day for Samoa.
Due to economic considerations, Samoa went from 2011-12-30 10:00-11:00
to 2011-12-30 10:00+13:00. Hence the country skipped 2011-12-30 in its
local time.
See https://stackoverflow.com/q/52084423/562769
A common wrong result here is 2011-12-30T23:59:00-10:00. This date never
happened in Samoa.
"""
tz = pytz.timezone('Pacific/Apia')
today_utc = datetime.datetime(2011, 12, 30, 9, 59,
tzinfo=datetime.timezone.utc)
today_tz = today_utc.astimezone(tz) # 2011-12-29T23:59:00-10:00
tomorrow = add_day(today_tz)
return tomorrow.isoformat() == '2011-12-31T23:59:00+14:00'
def test_dst(add_day):
"""Test if add_day properly increases the calendar day if DST happens."""
tz = pytz.timezone('Europe/Berlin')
today_utc = datetime.datetime(2018, 3, 25, 0, 59,
tzinfo=datetime.timezone.utc)
today_tz = today_utc.astimezone(tz) # 2018-03-25T01:59:00+01:00
tomorrow = add_day(today_tz)
return tomorrow.isoformat() == '2018-03-26T01:59:00+02:00'
to_test = [(add_day_dateutil_relativedelta, 'relativedelta'),
(add_day_datetime_timedelta, 'timedelta'),
(add_day_datetime_timedelta_conversion, 'timedelta+conversion'),
(add_day, 'timedelta+conversion+dst')]
print('{:<25}: {:>5} {:>5}'.format('Method', 'Samoa', 'DST'))
for method, name in to_test:
print('{:<25}: {:>5} {:>5}'
.format(name,
test_samoa(method),
test_dst(method)))
测试结果
Method : Samoa DST
relativedelta : 0 0
timedelta : 0 0
timedelta+conversion : 1 0
timedelta+conversion+dst : 1 1
89
要增加日期，可以使用叫做timedelta的对象：
import datetime
datetime.datetime.now() + datetime.timedelta(days=1)
你可以在Python的文档中查找timedelta对象的相关信息：http://docs.python.org/library/datetime.html
401
好的，下面是你提供的内容：
在编程中，有时候我们需要让程序在特定的条件下执行某些操作。比如说，当用户点击一个按钮时，我们希望程序能做出反应。这种反应通常是通过“事件”来实现的。事件就像是程序中的一个信号，告诉它发生了什么事情。
为了让程序能够处理这些事件，我们通常会使用“监听器”。监听器就像是一个守卫，它一直在关注特定的事件，一旦事件发生，它就会立即执行相应的代码。
举个例子，想象一下你在家里安装了一个门铃。每当有人按门铃时，门铃就会发出声音，提醒你有人来了。在这个例子中，门铃就是事件，而你听到声音的反应就像是监听器在工作。
在编程中，我们可以通过编写代码来设置这些监听器，让它们在事件发生时执行特定的操作。这种方式让我们的程序变得更加灵活和互动。
希望这个解释能帮助你理解事件和监听器的基本概念！
date = datetime.datetime(2003,8,1,12,4,5)
for i in range(5):
date += datetime.timedelta(days=1)
print(date)