【代碼】Lambda分組取最新時間數據

// 數據
List<LoginRecord> records = new List<LoginRecord>() {
                new LoginRecord(){ Id=1,Name="張三",LoginTime = DateTime.Now.AddDays(-6) },
                new LoginRecord(){ Id=2,Name="李四",LoginTime = DateTime.Now.AddDays(-3) },
                new LoginRecord(){ Id=3,Name="王五",LoginTime = DateTime.Now.AddDays(-2) },
                new LoginRecord(){ Id=4,Name="張三",LoginTime = DateTime.Now.AddDays(-1) },
                new LoginRecord(){ Id=5,Name="李四",LoginTime = DateTime.Now.AddDays(-4) },
            };

//第一種 分組后排序分組數據取第一個
records.GroupBy(g => g.Name).Select(p => p.OrderByDescending(t => t.LoginTime).FirstOrDefault());

//第二種 分組后取分組數據中的時間與最大時間相等的數據
records.GroupBy(g => g.Name).Select(p => p.FirstOrDefault(t => t.LoginTime == p.Max(s => s.LoginTime)));