How can I write foreach loop to sum elements in lamba expression?

Question

How can I write foreach loop shown below as a labmda expression?

var sum = 0;
foreach (SomeClass obj in SomeListOfClass)
{
   sum += obj.SomeValue;
}

I am expecting a lambda expression that look like this

var sum = SomeListOfClass.ForEachMethod( x => sum += x.SomeValue)

Is there any way to do it?

You could just use Linq's `Sum` extension method `var sum = SomeListOfClass.Sum(x => x.SomeValue);` — juharr, Mar 09 '16 at 18:06
This may help you: [http://stackoverflow.com/questions/858978/lambda-expression-using-foreach-clause](http://stackoverflow.com/questions/858978/lambda-expression-using-foreach-clause) — Dimitar Popov, Mar 09 '16 at 18:11
Why so many downvotes? What's exactly wrong with the question. Didn't understand? — talaa123, Mar 09 '16 at 20:42
@talaa123 Well, your code doesn't make much sense (why are you adding to `sum` in the lambda and also setting it to the return value?) and you apparently didn't look at the documentation, where you would find `Sum()` and `ForEach()`. You also didn't explain why do you want to use a lambda. — svick, Mar 12 '16 at 22:13

score 3 · Answer 1 · answered Mar 09 '16 at 18:06

3

Use Linq:

using System.Linq;

var sum = list.Sum(x => x.SomeValue);

answered Mar 09 '16 at 18:06

Michael Gunter

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score 2 · Answer 2 · answered Mar 09 '16 at 18:16

For the special case at hand (sum), you can use Linq's Sum method.

SomeListOfClass.Sum(c => c.Property);

This however, is just a special case of Aggregate. If you need more complicate aggregation of your list, you'd use that.
Here is an example that sums up the values of integers:

var ints = new List<int>() { 1, 2, 3 };
var x = ints.Aggregate((start, current) => start + current);

How can I write foreach loop to sum elements in lamba expression?

2 Answers2