How to use Linq to group every N number of rows

Question

Hi,

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 result would be 1,2,3 in first group then 4,5,6 in next group etc. I know how to get every nth record but what I need is all the records so I can then aggregate them, using first, last, sum, max, etc.

Thanks!

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);