How to use Linq to group every N number of rows

Question

I cannot find a way to make this work and hoping someone has an idea. A simplified example would be having a list of say integers 1-100, i want to group every 3 rows so the

Answer 1

var q = Enumerable.Range(0, 100).GroupBy(x => x/3);

Am I missing something?

Answer 2

This example should work for querying non-numeric collections. It projects an index into the object to be grouped, and then removes it again during the grouping.

var studentQuery2 = students
    .Select((student, index) => new {student, index})
    .GroupBy(g => g.index / 3, i => i.student);

Answer 3

How about a simpler approach:

var index = 0;
var grpOf3s = students.GroupBy(x => index++ / 3);

Update: If you are using the Key value of the group item then you will need to convert the group enumerable to a list. Otherwise you will get a different Key every time it is accessed.

var index = 0;
var grpOf3s = students.GroupBy(x => index++ / 3).ToList();