C#•2y ago

❔ Linq group by with multiple columns for the outer and then 1 other column for the inner group

Lets say I have a list of class Car. It has properties Id, Model, Year, Age,CarCode. A carCode is unique for a model but is not for all models. I want to group by Model and Year together and then group that grouping by Age and then for each Agegroup in each model and year group send Model, Age, and list<string>CarCodes to a method which will update a db table with those CarCodes. I found some pieces of code online but couldnt get anything to give me the thing I need.

  var grouped = bla
  .GroupBy(l => new { l.sreSif, l.sreSerija})//group by two things
   .Select(y => new { Element = y.Key,   })
  .GroupBy(f => f.Element.sreSerija)//this will become the outer grouping

//THEN I TRIED 
var consolidatedChildren =
    from c in bla
    group c by new
    {
       
        c.sreSif,
        c.sreSerija,
    } into gcs
    from g in gcs
    group g by new
    {
     g.sreIsplatio
    };

  var grouped = bla
  .GroupBy(l => new { l.sreSif, l.sreSerija})//group by two things
   .Select(y => new { Element = y.Key,   })
  .GroupBy(f => f.Element.sreSerija)//this will become the outer grouping

//THEN I TRIED 
var consolidatedChildren =
    from c in bla
    group c by new
    {
       
        c.sreSif,
        c.sreSerija,
    } into gcs
    from g in gcs
    group g by new
    {
     g.sreIsplatio
    };

this line of thinking did not work What I want

var carModelYearGroupList=GroupBy CarLIst(Model, Year)
var carAgeGL= groupBy carModelYearGroupList(key.Age)

Parallel.ForEach(carModelYearGroupList, new ParallelOptions { MaxDegreeOfParallelism = 10 }, (car) =>
           {
Parallel.ForEach(carAgeGL, new ParallelOptions { MaxDegreeOfParallelism = 10 }, (ca) =>
           {
              UpdateDb(Model m, Age a, List<string> carCodes); 
});
});

var carModelYearGroupList=GroupBy CarLIst(Model, Year)
var carAgeGL= groupBy carModelYearGroupList(key.Age)

Parallel.ForEach(carModelYearGroupList, new ParallelOptions { MaxDegreeOfParallelism = 10 }, (car) =>
           {
Parallel.ForEach(carAgeGL, new ParallelOptions { MaxDegreeOfParallelism = 10 }, (ca) =>
           {
              UpdateDb(Model m, Age a, List<string> carCodes); 
});
});

2 Replies

dino2dy•2y ago

My latest attempt

     var consolidatedChildren =
    from c in bla
    group c by new
    {
       
        c.sreSif,
        c.sreSerija,
    } into gcs
    from g in gcs
    group g by new
    {
     g.sreIsplatio
    } into gcse
     select new    
     {
         srecka= gcs.Key.sreSif,
         serija = gcs.Key.sreSerija,
         opBroj = gcse.Key.sreIsplatio,
         sreckeTemp = gcse.ToList(),
     };

            foreach (var c in consolidatedChildren)
            {
               foreach (var isp in c.sreckeTemp)
               {
                   
                   List<string>IsplatniBrojevi= new List<string>();
                   IsplatniBrojevi.Add(isp.sreIspBroj);
               }
            }

     var consolidatedChildren =
    from c in bla
    group c by new
    {
       
        c.sreSif,
        c.sreSerija,
    } into gcs
    from g in gcs
    group g by new
    {
     g.sreIsplatio
    } into gcse
     select new    
     {
         srecka= gcs.Key.sreSif,
         serija = gcs.Key.sreSerija,
         opBroj = gcse.Key.sreIsplatio,
         sreckeTemp = gcse.ToList(),
     };

            foreach (var c in consolidatedChildren)
            {
               foreach (var isp in c.sreckeTemp)
               {
                   
                   List<string>IsplatniBrojevi= new List<string>();
                   IsplatniBrojevi.Add(isp.sreIspBroj);
               }
            }

But I don't see gcs so those lines are showing me errors

 select new    
     {
         srecka= gcs.Key.sreSif,
         serija = gcs.Key.sreSerija,

 select new    
     {
         srecka= gcs.Key.sreSif,
         serija = gcs.Key.sreSerija,

Accord•2y ago

Looks like nothing has happened here. I will mark this as stale and this post will be archived until there is new activity.

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❔ Linq group by with multiple columns for the outer and then 1 other column for the inner group