CODEWITHSUNDEEP
c#asp.netlistgenerics
Praveen VR
Praveen VR

Reputation: 1564

Grouping in a generic list

I have a generic list:

  List<Test> lstReport = new List<Test>();
  lstReport.Add(new Test { ID = 1, Category = "Hot work", Approver = "Praveen" });
  lstReport.Add(new Test { ID = 1, Category = "Civil work", Approver = "Praveen" });
  lstReport.Add(new Test { ID = 1, Category = "Others", Approver = "Praveen" });
  lstReport.Add(new Test { ID = 4, Category = "Hot work", Approver = "Praveen" });
  lstReport.Add(new Test { ID = 5, Category = "Critical work", Approver = "Praveen" });

Now I want to take unique rows from the generic list by the ID value. For eg, I need to group the rows having same ID and if the existence of ID's more than once, then its Category field has to be changed to "Grouped".

How can I write this expression?

Upvotes: 0

Views: 1067

Answers (4)

Zein Makki
Zein Makki

Reputation: 30022

This Works:

    var QueryResult = (from x in lstReport
                        group x by x.ID into res
                        select new Test
                        {
                            ID = res.Key,
                            Category = res.Count() > 1 ? "Grouped" : res.First().Category,
                            Approver = res.First().Approver
                        }).ToList();

Upvotes: 1

Nahuel Ianni
Nahuel Ianni

Reputation: 3185

You can use Linq to group objects based on some property:

var list = lstReport.GroupBy(t => t.ID);

This will return a new collection with 3 items: IEnumerable<IGrouping<TKey, TSource>>; which basically means a collection containing a collection with one or more items.

Then you can iterate over that new collection and check if each item contains more than one subitem; if it does, then iterate over the subitems and modify the Category value.

http://msdn.microsoft.com/en-us/library/system.linq.enumerable.groupby(v=vs.110).aspx

Upvotes: 0

sjkm
sjkm

Reputation: 3937

List<Test> lstReport = new List<Test>();

...

var groups = lstReport.GroupBy(i => i.ID).ToList();

foreach(var group in groups) {
    var items = group.ToList();
    if(items.Count > 1)
        items.ForEach(i => { i.Category = "Grouped"; });
}

Upvotes: 1

Reza
Reza

Reputation: 19843

You can try this

var q = from r in lstReport
group r by r.ID into g
select new Test{ID=g.Key, Category = g.Count()>1? "Grouped" : g.Min(Category)};

also you can have g.Max(...) or g.Min(...)

Upvotes: 0

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