Question

I have an IEnumerable and I want to get a new IEnumerable containing every nth element.

Can this be done in Linq?

Answer 1

Just figured it out myself…

The IEnumerable<T>.Where() method has an overload that takes the index of the current element – just what the doctor ordered.

(new []{1,2,3,4,5}).Where((elem, idx) => idx % 2 == 0);

This would return

{1, 3, 5}

Update: In order to cover both my use case and Dan Tao’s suggestion, let’s also specify what the first returned element should be:

var firstIdx = 1;
var takeEvery = 2;
var list =  new []{1,2,3,4,5};

var newList = list
    .Skip(firstIdx)
    .Where((elem, idx) => idx % takeEvery == 0);

…would return

{2, 4}