CODEWITHSUNDEEP
c#linq
Sam
Sam

Reputation: 45

Summing up property values using LinQ

I've a List of custom objects called Product: List

class Product
{
    string Key1 {get; set;}
    string Key2 {get; set;}
    int Count1 {get; set;}
    int Count2 {get; set;}
}

I'm combining multiple Product lists and I need to create a new list which will have sum values for each of the Count properties. For e.g.

List 1:
"Key1", "Key2", 1, 2
"Key2", "Key3", 3, 4

List 2:
"Key1", "Key2", 5, 6
"Key2", "Key3", 7, 8

So my new List should be:

New List:
"Key1", "Key2", 6, 8
"Key2", "Key3", 10, 12

Can someone help me on this please?

Thanks.

Upvotes: 0

Views: 49

Answers (2)

Gaurang Dave
Gaurang Dave

Reputation: 4046

 List<Product> lst1 = new List<Product>();
 List<Product> lst2 = new List<Product>();

 lst1.Add(new Product() {Key1 = "K1",Key2 ="K2", Count1 =1, Count2=2 });
 lst1.Add(new Product() { Key1 = "K2", Key2 = "K3", Count1 = 3, Count2 = 4 });

 lst2.Add(new Product() { Key1 = "K1", Key2 = "K2", Count1 = 5, Count2 = 6});
 lst2.Add(new Product() { Key1 = "K2", Key2 = "K3", Count1 = 7, Count2 = 8 });
// Way 1
 var l = lst1.Join(lst2, l1 => l1.Key1, l2 => l2.Key1, 
                (lt1, lt2) => new Product { Key1 = lt1.Key1, Key2 = lt1.Key2, Count1 = lt1.Count1 + lt2.Count1, Count2 = lt1.Count2 + lt2.Count2 } ).ToList() ;

// Way 2
var result = lst1.Join(lst2, x => new { x.Key1, x.Key2 },
                 y => new { y.Key1, y.Key2 }, (x, y) => 
                 new Product { Key1 = x.Key1, Key2 = x.Key2, Count1 = x.Count1 + y.Count1, Count2 = x.Count2 + y.Count2 }).ToList();

Upvotes: 0

TheGeneral
TheGeneral

Reputation: 81493

You can do this

var list1 = new List<Product>()
   {
      new Product(){Key1 = "Key1", Key2 ="Key2", Count1 = 1, Count2 = 2},
      new Product(){Key1 = "Key2", Key2 ="Key3", Count1 = 1, Count2 = 2}
   };

var list2 = new List<Product>()
   {
      new Product(){Key1 = "Key1", Key2 ="Key2", Count1 = 6, Count2 = 8},
      new Product(){Key1 = "Key2", Key2 ="Key3", Count1 = 10, Count2 = 12}
   };

var result = list1.Concat(list2)
                  .GroupBy(x => new {x.Key1,x.Key2})
                  .Select(x => new
                     {
                        x.Key.Key1,
                        x.Key.Key2,
                        SumCount1 = x.Sum(y => y.Count1),
                        SumCount2 = x.Sum(y => y.Count2)
                     }).ToList();

Output

Demo Here

Key1, Key2, 7, 10
Key2, Key3, 11, 14

Additional Resources

List.AddRange

Adds the elements of the specified collection to the end of the List.

Enumerable.GroupBy Method (IEnumerable, Func, Func)

Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function.

Enumerable.Concat Method (IEnumerable, IEnumerable)

Concatenates two sequences.

Upvotes: 2

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