Group by with multiple columns using lambda

Question

How can I group by with multiple columns using lambda?

I saw examples of how to do it using linq to entities, but I am looking for lambda form.

Answer 1

if your table is like this

rowId     col1    col2    col3    col4
 1          a       e       12       2
 2          b       f       42       5
 3          a       e       32       2
 4          b       f       44       5


var grouped = myTable.AsEnumerable().GroupBy(r=> new {pp1 =  r.Field("col1"), pp2 = r.Field("col2")});