C# Linq double groupby need min/max for hourly values once per day -


i have been playing around awhile , can't quite result looking for.

i have object this:

public class point {     public string tag {get;set;}     public datetime time {get;set;}     public int value {get;set;} }

each tag have 24 values per day (one per hour). data (tag / time / value):

x / 5-15-2015 - 0100 / 10  x / 5-15-2015 - 0200 / 20  x / 5-15-2015 - 0300 / 30  y / 5-15-2015 - 0100 / 20  y / 5-15-2015 - 0200 / 30  x / 5-16-2015 - 0100 / 10

for example...

i sort tag , date, min/max/avg 24 hrs in each day. goal create following object.

public class newpoint {     public string tag {get;set;}     public datetime date {get;set;}     public int lowvalue {get;set;}     public int highvalue {get;set;}     public int avgvalue {get;set;} }

where resulting objests (tag / date / lowvalue / highvalue / avgvalue):

x / 5-15-2015 / 10 / 30 / 20  y / 5-15-2015 / 20 / 30 / 25  x / 5-16-2015 / 10 / 10 / 10

i having issues with: 

group list new {list.tag, list.time.tostring("d") } dategroup

i think going need 2 linq statements. 1 group tag , date find min/max/avg each tag/date, , grab date[0] (or distinct date per tag) along min/max/avg pass newpoint object.

advice welcome, thanks!

no need 2 statements @ all... nor using string conversion. use key of each group, , datetime.date property:

var query = list.groupby(x => new { x.tag, x.time.date })                 .select(g => new newpoint                         {                             tag = g.key.tag,                             date = g.key.date,                             lowvalue = g.min(x => x.value),                             highvalue = g.max(x => x.value),                             avgvalue = (int) g.average(x => x.value)                         });

the cast avgvalue required because return type of average double - might want consider changing property type instead.


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