Question

我无法弄清楚如何用年，日和星期来回月。现在我只是想开发一个可以做到这一点的Python脚本。完成此脚本后的目标是将其用于Spark SQL查询以查找月份，因为在我的数据中，每行给出一天，一年和一周。

截至目前，我的python代码看起来像这样。此代码仅适用于我在print中的语句（getmonth（2,30,2018）返回7.我已经尝试了其他日期，输出只是“无”。我也尝试了变量，但没有成功。< / p>

import datetime

def month(day, week, year):
    for month in range(1,13):
        try:
            date = datetime.datetime(year, month, day)
        except ValueError:
            iso_year, iso_weeknum, iso_weekday = date.isocalendar()
            if iso_weeknum == week:
                return date.month
print(getmonth(2, 30, 2018))


#iso_(year,weeknum,weekday) are the classes for ISO. Year is 1-9999, weeknum is 0-52 or 53, and weekday is 0-6
#isocaldenar is a tuple (year, week#, weekday)

Answer 1

可以使用pendulum库创建更简单的解决方案。与您的代码一样，循环显示月份数字，创建日期，将这些日期的周数与所需日期进行比较。如果发现停止循环;如果没有看到日期，则退出循环，例如-1。

>>> import pendulum
>>> for month in range(1,13):
...     date = pendulum.create(2018, month, 28)
...     if date.week_of_year == 30:
...         break
... else:
...     month = -1
...     
>>> month
7
>>> date
<Pendulum [2018-07-28T00:00:00+00:00]>

Answer 2

这是一个蛮力方法，循环一年中的几天（它预计星期一为0，星期日为6，它还返回索引的月0，1月为0，12月为11）：

import datetime

def month(day, week, year):
    #Generate list of No of days of the month
    months = [31,28,31,30,31,30,31,31,30,31,30,31]
    if((year % 4 == 0 and year % 100 != 0) or year % 400 == 0): months[1] += 1

    #ISO wk1 of the yr is the first wk with a thursday, otherwise it's wk53 of the previous yr
    currentWeek = 1 if day < 4 else 0

    #The day that the chosen year started on
    currentDay = datetime.datetime(year, 1, 1).weekday()

    #Loop over every day of the year
    for i in range(sum(months)):
        #If the week is correct and day is correct you're done
        if day == currentDay and week == currentWeek:
            return months.index(next(filter(lambda x: x!=0, months)))

        #Otherwise, go to next day of wk/next wk of yr
        currentDay = (currentDay + 1) % 7
        if currentDay == 0:
            currentWeek += 1

        #And decrement counter for current month
        months[months.index(next(filter(lambda x: x!=0, months)))]-=1

print(month(2, 30, 2018)) # 6 i.e. July

months.index(next(filter(lambda x: x!=0, months)))用于获取我们尚未使用的所有日期的第一个月，即您当前所在的月份。

Answer 3

我真的不明白你的问题，但我认为日期时间会有效...... sorce: Get date from ISO week number in Python：

>>> from datetime import datetime
>>> day = 28
>>> week = 30
>>> year = 2018
>>> t = datetime.strptime('{}_{}_{}{}'.format(day,week,year,-0), '%d_%W_%Y%w')
>>> t.strftime('%W')
'30'
>>> t.strftime('%m')
'07'
>>>

从日，周和年Python中寻找月份

3 个答案: