Python中的四舍五入日期答案

【问题标题】：Rounding dates in PythonPython中的四舍五入日期
【发布时间】：2014-05-05 04:18:06
【问题描述】：

假设我正在查看特定日期：

from datetime import date, timedelta
days_to_substract = 65
my_date = date.today()-timedelta(days=days_to_subtract)

我怎样才能找到：

Monday 在my_date 之前的日期（如果my_date 不是星期一）
Monday 与 my_date 最接近的日期

有没有办法在datetime 中舍入日期？

【问题讨论】：

标签： python datetime

【解决方案1】：

你可以使用 dateutil

from datetime import *
from dateutil.relativedelta import *

days_to_substract = 64
my_date   = (date.today()-timedelta(days=days_to_substract))
next=my_date+relativedelta(weekday=MO)
previous=my_date+relativedelta(weekday=MO(-1))
print ('mydate is %s' %my_date)
print ('next monday is %s' %next)
print ('previous monday is %s' %previous)

diff1=my_date-previous
diff2=next-my_date
if diff2<diff1:
    print ('Closest monday is %s' %next)
else:
    print ('Closest monday is %s' %previous)

将输出：

mydate is 2014-01-21
next monday is 2014-01-27
previous monday is 2014-01-20
Closest monday is 2014-01-20

【讨论】：

下周一不是更准确，最接近的是绝对差值最小的两个吗？

【解决方案2】：

使用工作日：

from datetime import date, timedelta
d=["Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"]
days_to_substract = 65
my_date = (date.today()-timedelta(days=days_to_substract))
t=my_date.weekday()
print "Today is ",d[t]," Wait ",(6-t+1)," days for Monday"

输出：

Today is  Monday  Wait  7  days for Monday

【讨论】：

6-t+1 只是7-t :)

【解决方案3】：

您可以使用 date.weekday (http://docs.python.org/2/library/datetime.html#datetime.date.weekday) 来查找“my_date”的工作日整数值。然后您可以使用当前工作日的差异（例如，工作日 = 2 表示星期三）并执行另一个 timedelta 计算。当我尝试时，这对我有用：

from datetime import *

days_to_subtract = 65
my_date = (date.today() - timedelta(days=days_to_subtract))
dow = my_date.weekday()
monday_my_date = (my_date - timedelta(days=dow))

print(monday_my_date)

祝你好运！

【讨论】：