Aggregate Function

Hi Srinivas,

Here is a small exmple which explains about aggregate function for list.

            List numlist = new List();
            numlist.Add(1);
            numlist.Add(2);
            numlist.Add(3);
            numlist.Add(4);

            int mySum = numlist.Aggregate(1, (s, n) => s + n);

            int myProduct = numlist.Aggregate((s, n) => s * n);

            int myDifference = numlist.Aggregate((s, n) => s - n);

            Console.WriteLine("Sum is: " + mySum.ToString());

            Console.WriteLine("Difference is: " + myDifference.ToString());

            Console.WriteLine("Product is: " + myProduct.ToString());

If you add this to a project and run, you will get following result.

Sum is: 11
Difference is: -8
Product is: 24

For aggregate method, the first parameter (optional parameter) is the seed. It means the initial value of the accumulator.

int mySum = numlist.Aggregate(1, (s, n) => s + n);

That's why this returned 11 instead of 10.

Second parameter is the function used. Here, the function is given as a lambda expression.

Lambda expression is somthing like this,

(input parameters) => expression

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2 Replies

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Nilanka Dharmadasa16y ago
Accepted answer
Hi Srinivas,

Here is a small exmple which explains about aggregate function for list.

List
numlist = new List();
            numlist.Add(1);
            numlist.Add(2);
            numlist.Add(3);
            numlist.Add(4);

            int mySum = numlist.Aggregate(1, (s, n) => s + n);

            int myProduct = numlist.Aggregate((s, n) => s * n);

            int myDifference = numlist.Aggregate((s, n) => s - n);

            Console.WriteLine("Sum is: " + mySum.ToString());

            Console.WriteLine("Difference is: " + myDifference.ToString());

            Console.WriteLine("Product is: " + myProduct.ToString());

If you add this to a project and run, you will get following result.

Sum is: 11
Difference is: -8
Product is: 24

For aggregate method, the first parameter (optional parameter) is the seed. It means the initial value of the accumulator.

int mySum = numlist.Aggregate(1, (s, n) => s + n);

That's why this returned 11 instead of 10.

Second parameter is the function used. Here, the function is given as a lambda expression.

Lambda expression is somthing like this,

(input parameters) => expression

If you find my answer helpful, please tick 'Do you like this answer' checkbox.
srinivas16y ago
thank you very much your example is very nice and I totaly understood about aggregate function