使用 LINQ 显示时间跨度内每小时的平均值

Question

我有一个Part 列表，其中包含一个DateTime 值，表示它们何时注册到我的Database。

我想显示每小时白班登记的人数和每晚登记的人数。

我试图将我的总体平均逻辑基于这两个值

@{

var shiftChangeTime = new TimeSpan(16, 0, 0);
<table>
    <tr>
        @*This is my general average*@
        <td>Number of part/hour</td>
        @{
            var avg = Model.GroupBy(x => ((DateTime)x.ScanTime).TimeOfDay.Hours)
                        .Average(x => x.Count());
            <td>@(Math.Round(avg, 2))</td>
        }
    </tr>
    <tr>
        @*This is my day average*@
        <td>Number of part/hour</td>
        @{
            var avgDay = Model.GroupBy(x => ((DateTime)x.ScanTime).TimeOfDay < shiftChangeTime, y => ((DateTime)y.ScanTime).TimeOfDay.Hours)
                        .Average(x => x.Count());
            <td>@(Math.Round(avgDay, 2))</td>
        }
    </tr>
    <tr>
        @*This is my night average*@
        <td>Number of part/hour for night shift</td>
        @{
            var avgNight = Model.GroupBy(x => ((DateTime)x.ScanTime).TimeOfDay > shiftChangeTime, y => ((DateTime)y.ScanTime).TimeOfDay.Hours)
                        .Average(x => x.Count());
            <td>@(Math.Round(avgNight, 2))</td>
        }
    </tr>
</table>
}

我目前坚持以小时为单位区分日班/夜班的逻辑。

现在它把我的总数一分为二。

知道如何进行吗？

Answer 1

您上面的代码的问题是，在 GroupBy 的日/夜班之后，您还需要按 Hour 分组，以便进行每小时平均。

这会为您提供白天/夜班期间一小时内的平均零件数：

List<Part> Model = new List<Part>
{
    new Part{ ScanTime = new DateTime(2016,1,1,1,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,4,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,4,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,4,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,4,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,7,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,12, 0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,17,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,19,0,0) },
    new Part{ ScanTime = new DateTime(2016,1,1,23,0,0) },
};

var shiftChangeTime = new TimeSpan(12, 0, 0);

var result = Model.GroupBy(x => x.ScanTime.TimeOfDay < shiftChangeTime ? "Day" : "Night")
     .Select(g => new
     {
         Shift = g.Key,
         Average = g.GroupBy(item => item.ScanTime.Hour, 
                             (key, group) => new { Hour = key, Amount = group.Count() })
                    .Average(y => y.Amount)
     }).ToList();

如果您不想要 2 个 GroupBy，另一种选择是首先使用 Where 仅保留特定班次的记录，然后再保留其余部分：

var dayAverage = Model.Where(x => x.ScanTime.TimeOfDay < shiftChangeTime)
                      .GroupBy(item => item.ScanTime.Hour, 
                               (key, group) => new { Hour = key, Amount = group.Count() })
                      .Average(y => y.Amount);