c# linq分组 lambda分组

                var groupResults = from gr in models
                                   where gr.Noise != 0 && gr.Temperature != 0 && gr.Humidity != 0 && gr.Pm25 != 0
                                   group gr by new { gr.IP, gr.Name, gr.Port } into g
                                   select new
                                   {
                                       g.Key.IP,
                                       g.Key.Name,
                                       g.Key.Port,
                                       NoiseAvg = g.Average(m => m.Noise),
                                       NoiseMax = g.Max(m => m.Noise),
                                       NoiseMin = g.Min(m => m.Noise),
                                       TemperatureAvg = g.Average(m => m.Temperature),
                                       TemperatureMax = g.Max(m => m.Temperature),
                                       TemperatureMin = g.Min(m => m.Temperature),
                                       HumidityAvg = g.Average(m => m.Humidity),
                                       HumidityMax = g.Max(m => m.Humidity),
                                       HumidityMin = g.Min(m => m.Humidity),
                                       Pm25Avg = g.Average(m => m.Pm25),
                                       Pm25Max = g.Max(m => m.Pm25),
                                       Pm25Min = g.Min(m => m.Pm25),
                                       CollectTime = g.FirstOrDefault().CreatedTime
                                   };

                var groupResults2 = models.Where(m => m.Noise != 0 && m.Temperature != 0 && m.Humidity != 0 && m.Pm25 != 0)
                                        .GroupBy(m => new { m.IP, m.Name, m.Port }).Select(g => new
                                        {
                                            g.Key.IP,
                                            g.Key.Name,
                                            g.Key.Port,
                                            NoiseAvg = g.Average(m => m.Noise),
                                            NoiseMax = g.Max(m => m.Noise),
                                            NoiseMin = g.Min(m => m.Noise),
                                            TemperatureAvg = g.Average(m => m.Temperature),
                                            TemperatureMax = g.Max(m => m.Temperature),
                                            TemperatureMin = g.Min(m => m.Temperature),
                                            HumidityAvg = g.Average(m => m.Humidity),
                                            HumidityMax = g.Max(m => m.Humidity),
                                            HumidityMin = g.Min(m => m.Humidity),
                                            Pm25Avg = g.Average(m => m.Pm25),
                                            Pm25Max = g.Max(m => m.Pm25),
                                            Pm25Min = g.Min(m => m.Pm25),
                                            CollectTime = g.FirstOrDefault().CreatedTime,
                                        });

 两者效果一样