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我怎样才能获得两天之间的所有日子?

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我需要两天之间的所有工作日 .

例:

Wednesday - Friday  = Wednesday, Thursday, Friday  
        3 - 5       = 3, 4, 5

 Saturday - Tuesday = Saturday, Sunday, Monday, Tuesday
        6 - 2       = 6, 7, 1, 2

我很确定有一个聪明的算法来解决这个问题 . 我能想到的唯一算法是使用循环或 if 语句 .

必须有一种优雅的方法来解决这个问题 . 我在工作日使用数字1-7,但0-6也很好 .

我能想到的最好的:

def between(d1, d2):
     alldays = [0,1,2,3,4,5,6,0,1,2,3,4,5,6]    # or range(7) * 2
     offset = 8 if d1 > d2 else 1
     return alldays[d1:d2 + offset]

between(0, 4)
# [0,1,2,3,4]

between(5,2)
# [5,6,0,1,2]

7 回答

  • 2
    >>> def weekdays_between(s, e):
    ...     return [n % 7 for n in range(s, e + (1 if e > s else 8))]
    ... 
    >>> weekdays_between(2, 4)
    [2, 3, 4]
    >>> weekdays_between(5, 1)
    [5, 6, 0, 1]
    

    如果你必须从/转换到实际天数,它会更复杂一些 .

    >>> days = 'Mon Tue Wed Thu Fri Sat Sun'.split()
    >>> days_1 = {d: n for n, d in enumerate(days)}
    >>> def weekdays_between(s, e): 
    ...     s, e = days_1[s], days_1[e]
    ...     return [days[n % 7] for n in range(s, e + (1 if e > s else 8))]
    ... 
    >>> weekdays_between('Wed', 'Fri')
    ['Wed', 'Thu', 'Fri']
    >>> weekdays_between('Sat', 'Tue')
    ['Sat', 'Sun', 'Mon', 'Tue']
    
  • 0

    怎么样(在伪代码中):

    weekday[] = {"Mon" .. "Sun"}
    for(i = wkday_start; (i % 7) != wkday_end; i = (i+1) % 7)
        printf("%s ", weekday[i]);
    

    它的工作方式类似于循环缓冲区,wkday_start是从(从0开始)开始的索引,wkday_end是结束索引 .

    希望这可以帮助

    乔治 .

  • 0

    excellent answer from Stephan202的基础上,您可以概括圆形切片的概念 .

    >>> def circular_slice(r, s, e):
    ... return [r[n % len(r)] for n in range(s, e + (1 if e>s else len(r)+1))]
    ...
    >>> circular_slice(range(0,7), 2, 4)
    [2, 3, 4]
    >>> circular_slice(range(0,7), 5, 1)
    [5, 6, 0, 1]
    >>> circular_slice('Mon Tue Wed Thu Fri Sat Sun'.split(), 5, 1)
    ['Sat', 'Sun', 'Mon', 'Tue']
    
  • 1

    提供的解决方案已经回答了问题,但我想提出一些额外的建议 . 我不知道你在做什么,但也许你想要实际日期呢?

    >>> from datetime import timedelta, date
    >>> from dateutil.rrule import rrule, DAILY
    >>> today = date(2009, 10, 13) # A tuesday
    >>> week = today - timedelta(days=6)
    >>> list(rrule(DAILY, byweekday=xrange(5), dtstart=week, until=today))
    [datetime.datetime(2009, 10, 7, 0, 0),
     datetime.datetime(2009, 10, 8, 0, 0),
     datetime.datetime(2009, 10, 9, 0, 0),
     datetime.datetime(2009, 10, 12, 0, 0),
     datetime.datetime(2009, 10, 13, 0, 0)]
    

    这使用了优秀的python-dateutil模块 .

  • 1

    使用日历模块作为日期名称列表:

    import calendar
    
    def intervening_days(day1, day2):
        weektest = list(calendar.day_name)*2
        d1 = weektest.index(day1)
        d2 = weektest.index(day2,d1+1)
        return weektest[d1:d2+1]
    
    print intervening_days("Monday","Sunday")
    print intervening_days("Monday","Tuesday")
    print intervening_days("Thursday","Tuesday")
    print intervening_days("Monday","Monday")
    

    打印:

    ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
    ['Monday', 'Tuesday']
    ['Thursday', 'Friday', 'Saturday', 'Sunday', 'Monday', 'Tuesday']
    ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday', 'Monday']
    

    如果您不希望星期一到星期一返回整整一周的天数,请将d2的确定更改为 d2 = weektest.index(day2,d1) .

  • 9

    你问了一个算法,我明白这应该是语言独立的;但是,以下代码使用C#和LINQ表达式:

    DayOfWeek start = DayOfWeek.Wednesday;
    DayOfWeek end = DayOfWeek.Friday;
    
    IEnumerable<DayOfWeek> interval = 
        Enum.GetValues(typeof(DayOfWeek)).OfType<DayOfWeek>()
            .Where(d => d >= start && d <= end);
    
    Console.WriteLine(
        String.Join(", ", 
            interval.Select(d => d.ToString()).ToArray()));
    

    也许,使用任何语言,您应该将值归因于每一天( Sunday=0 等)并查找与您所需的间隔匹配的所有值 .

  • 8

    以下代码在星期一 - 星期一返回1 .

    bool isWeekday(int d) {
        return d >= 1 && d <= 5;
    }
    
    int f(int d1, int d2) {
        int res = isWeekday(d1) ? 1 : 0;
        return d1 == d2 ?
               res :
               res + f(d1 % 7 + 1, d2);
    }
    

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