Conversion for loop using lambda (C # 3.0)

Question

How to convert below code

double sumxy = 0;

for (int i = 0; i < x.Count; i++)
{sumxy = sumxy + (x[i] * y[i]);}

using lambda

I am using C # 3.0. x and y are a list of double numbers

thanks

+2

Newbie 06 May '10 at 13:10

3 answers

It doesn't really make sense, but if you want:

Enumerable.Range(0, x.Count).Select(i => x[i] * y[i]).Sum();

+3

SLaks 06 May '10 at 13:15

Something like that...

var sumy = Enumerable.Range(0, x.Count).Aggregate((result, i) => result + (x[i]*y[i]);

0

Brian genisio 06 May '10 at 13:17

Jon Skeet · Accepted Answer · 2010-05-06T13:16:33+0000

If you are using .NET 4 you can use the operator Zip

:

double sumxy = x.Zip(y, (a, b) => a * b).Sum();

Or in .NET 3.5:

double sumxy = x.Select((value, index) => value * y[index]).Sum();