c# - 合并连续的日期期间

Question

我有一个日期周期列表，这些周期不重叠

|StartDate| EndDate|
| null    |  1/12  |
| 2/12    |  null  |
| null    |  4/12  |
| 6/12    |  8/12  |
| 9/12    |  null  |
| null    |  10/12 |
| 11/12   |  null  |

我必须将这些句点组合成如下所示的列表:

|StartDate| EndDate|
| null    |  1/12  |
| 2/12    |  4/12  |
| 6/12    |  8/12  |
| 9/12    |  10/12 |
| 11/12   |  null  |

这是我的解决方案，但我认为这不是一个聪明的方法

        var dateList = periodList.SelectMany(x => new[] { 
            new {Date = x.Item1, type = "S"}, 
            new {Date = x.Item2, type = "E"} 
        }).Where(x => x.Date != null).OrderBy(x => x.Date).ToArray();

        var result = new List<Tuple<DateTime?, DateTime?>>();
        int i = 0;
        do
        {
            if (i == 0 && dateList[i].type == "E")
            {
                result.Add(new Tuple<DateTime?, DateTime?>(null, dateList[i].Date));
            }
            else if (i + 1 == dateList.Count() && dateList[i].type == "S")
            {
                result.Add(new Tuple<DateTime?, DateTime?>(dateList[i].Date, null));
            }
            else
            {
                if (dateList[i].type == "S" && dateList[i+1].type == "E")
                {
                    result.Add(new Tuple<DateTime?, DateTime?>(dateList[i].Date, dateList[i + 1].Date));
                    i++;
                }                    
            }
            i++;
        } while (i < dateList.Count());

Answer 1

我的解决方案可能看起来更长，但它更干净在我看来。我认为你有 Period 类(而不是 Tuple<DateTime?, DateTime?> )如下:

public class Period
{
    public DateTime? StartDate { get; set; }
    public DateTime? EndDate { get; set; }
}

将您的日期添加到周期列表:

// Make list of periods ready
List<Period> periodList = //Prepare periods;

通过消除 null 获取开始日期和结束日期separately:

// Get start dates
List<DateTime> startDates = periodList
    .Where(p => p.StartDate.HasValue)
    .Select(p => p.StartDate.Value)
    .ToList();

// Get end dates
List<DateTime> endDates = periodList
    .Where(p => p.EndDate.HasValue)
    .Select(p => p.EndDate.Value)
    .ToList();

然后做其他操作:

// Clear list of periods
periodList.Clear();

// Add start dates which are bigger than LAST end date with NULL end date period
startDates.Where(s => s > endDates.Max())
    .ToList()
    .ForEach(s => periodList.Add(new Period() { StartDate = s, EndDate = null }));

// Add end dates which are smaller than FIRST start date with NULL start date period
endDates.Where(e => e < startDates.Min())
    .ToList()
    .ForEach(e => periodList.Add(new Period() {StartDate = null, EndDate = e}));

// Match other dates and add them to list
startDates.Where(s => s < endDates.Max())
    .ToList()
    .ForEach(s => periodList.Add(new Period()
                                {
                                    StartDate = s,
                                    EndDate = endDates.Where(e => e > s).Min()
                                }));

// Oder period list
periodList = periodList.OrderBy(p => p.StartDate).ToList();

您可以测试 .NET Fiddle 演示 here .

希望对您有所帮助。