Question

我用c＃编程。我得到了DateTimes的列表，可能是这样的（我只对这些日子感兴趣）：

12/07/2013,
12/07/2013,
12/06/2013,
12/05/2013,
12/04/2013,
12/04/2013,
11/11/2013,
11/10/2013,
11/04/2013.

换句话说，日期列表可以包含更多相同的日期。这些日子代表了测量值，这就是为什么它可以包含更多当天的测量值。我需要检查日期列表是否允许连续3天：

11/11/2013,
11/10/2013,
11/09/2013.

我的代码如下：

public static void longTimeAnalyse(string cpr)
    {
        List<DateTime> dayList = getDaylist(cpr);
        dayList.sort();
        DateTime current = DateTime.now.Date;

        if(dayList.count() != 0)
        {
            //check in the dayList if there is any days in a row?? How do i do that?
        }
    }

Answer 1

这是一个扩展方法，它将在集合中返回任意数量的连续日期：

static class EnumerableExtensions
{
    public static IEnumerable<IEnumerable<DateTime>> GetConsecutiveDays(this IEnumerable<DateTime> data,
                                                                        int consecutiveDayCount)
    {
        if (data == null)
        {
            throw new ArgumentNullException("data");
        }

        if (consecutiveDayCount < 2)
        {
            throw new ArgumentException("consecutiveDayCount should be greater than 1");
        }

        var days = data.Select(item => item.Date).Distinct().OrderBy(item => item);

        return days.Select((day, index) => days.Skip(index).Take(consecutiveDayCount).ToList())
                   .Where(group => group.First().AddDays(consecutiveDayCount - 1) == group.Last());
    }
}

测试方法（使用NUnit和FluentAssertions）：

[TestFixture]
public class ConsecutiveDaysTests
{
    [Test]
    public void ConsecutiveDayTest()
    {
        var dayList = new List<DateTime>
        {
            new DateTime(2013,12,07),
            new DateTime(2013,12,07),
            new DateTime(2013,12,06),
            new DateTime(2013,12,05),
            new DateTime(2013,12,04),
            new DateTime(2013,12,04),
            new DateTime(2013,11,11),
            new DateTime(2013,11,10),
            new DateTime(2013,11,04)
        };


        var result = dayList.GetConsecutiveDays(3).ToList();

        result.Should().HaveCount(2);
        result.First().ShouldBeEquivalentTo(new[]{new DateTime(2013,12,06),
                                                  new DateTime(2013,12,05),
                                                  new DateTime(2013,12,04)});
    }
}

检查日期列表是否连续几天

1 个答案: