Question

I have a class named HardwarePerformance contain these fields: time,cpuUsagePercent,memoryUsagePercent,diskUsage,diskRead,diskWrite,latency.
I had fill a List object to contain the not statistics data.
I need to calculating the average value for all these fields in a Linq command.
I don’t know how to get the average value with Linq. Follow is the code I wrote (It’s incorrect of course).

var _hardwarePerf = (from _stats in _statsList 
                    where _time>=DateTime.Parse("2012-04-04 00:00:00")
                        &&_time<=DateTime.Parse("2012-04-04 11:00:00") 
                    select new {
                           Latency = _stats.latency, 
                           CpuUsagePercent = _stats.cpuUsagePercent, 
                           MemoryUsagePercent = _stats.memoryUsagePercent, 
                           DiskUsage = _stats.diskUsage, DiskRead = _stats.diskRead, 
                           DiskWrite = _stats.diskWrite
                    }).Average(Latency => Latency.Latency);

The syntax of this code is correct. But I want to calculating all the average value at the same time, how do I write my code?

Answer 1

You can use “Group By” then you can use an average projection to calculate.

var query = from _stats in _statsList 
    group _stats by new {
               Latency = _stats.latency, 
               CpuUsagePercent = _stats.cpuUsagePercent, 
               MemoryUsagePercent = _stats.memoryUsagePercent, 
               DiskUsage = _stats.diskUsage, 
               DiskRead = _stats.diskRead, 
               DiskWrite = _stats.diskWrite

    } into myGroup
    select new {
        AverageVal = myGroup.Average(x => x.Value),
        CpuUsagePercent = myGroup.Key.CpuUsagePercent,
        ... // the rest of your projection
};

LINQ Average