CODEWITHSUNDEEP
c#
David Dury
David Dury

Reputation: 5717

c# list aggregate calculations alghoritm

Following scenario:

public class Data
{
   public Data()
   {
        Details = new List<Details>();
   }

   public List<Details> Details {get; set;}
}

public class Details
{
   public Details()
   {

   }

   public decimal A {get; set;}
   public decimal B {get, set;}
}

Later in the code:

Data dt = new Data();

Details det = new Details();
det.A = 2;    

dt.Details.Add(det); // add X amount of details to the list
.........

Now the list will look like this:

Item 1:  A = 2 , B = 0
Item 2:  A = 2 , B = 0
Item 3:  A = 2 , B = 0
Item 4:  A = 2 , B = 0
.....
Item N:  A = 2 , B = 0

How can I calculate the B property value like this:

enter image description here

Basically:

Item 1 A is the starting point and has whatever value ...

Item 1 B value will always be the same as Item 1 A

Item 2 A can be whatever

Item 2 B = Item 1 B + Item 2 A

Item 3 A can be whatever

Item 3 B = Item 2 B + Item 3 A

and so forth.

How can I iterate through the list and automatically calculate the B property value of the items?

Upvotes: 0

Views: 92

Answers (2)

Magnus
Magnus

Reputation: 46947

This should do it:

var prev = new Details();
foreach (var item in dt.Details)
{
    item.B = item.A + prev.B;
    prev = item;
}

Upvotes: 1

ryanyuyu
ryanyuyu

Reputation: 6486

It seems you just need a running sum stored into each variable. To do this, just modify a normal running sum approach and store it into the detail.

decimal currentSum = 0;
for (int i = 0; i < detailList.Count; i++)
{
    var detail = detailList[i];
    currentSum += detail.A;
    detail.B = currentSum;
}

Since you mentioned that you are not making this calculation often (your list does not change frequently), this should more than handle the job.

Upvotes: 0

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