Question

考虑简单的类

public class Data
{
    public DateTime Date;
    public object Content;
}

现在我有一个名为IEnumerable<Data>的{{1}}，我希望Linq能够对每天的旧项目进行排序。如果有同一天的项目，我只对当天的最新项目感兴趣。

Linq可以实现吗？

Answer 1

以下是如何做到这一点：

  var processInfo = new ProcessStartInfo("cmd.exe", "/c " + command);
            processInfo.CreateNoWindow = true;
            processInfo.UseShellExecute = true;
            processInfo.WindowStyle = ProcessWindowStyle.Maximized;
            processInfo.RedirectStandardError = true;
            processInfo.RedirectStandardOutput = true;

            var process = Process.Start(processInfo);

为了更具可读性，您还可以在var result = datas //Group by day (we don't include time here) .GroupBy(x => x.Date.Date) //For each group (day), get most recent item (we include time here) .Select(g => g.OrderByDescending(x => x.Date).First()) .ToList();声明中使用x.TimeOfDay代替x.Date。

Answer 2

使用此：

var result = from x in datas
        group x by x.Date.Date into g
        select g.OrderByDescending(x => x.Date).FirstOrDefault();

或者

var result = datas.GroupBy(x => x.Date.Date)
            .Select(g => g.Where(x => x.Date == g.Max(y => y.Date))
            .First());

选择每天的最新条目

2 个答案: