c# - Using Linq to remove duplicate by column values based on a second column -

i have datatable 2 columns "dt" , "asof", both dates. there rows has duplicate values of dt, find doing:

      var duplicategroups = dt.asenumerable()                                   .groupby(row => row.field<sqldatetime>("dt"))                                   .where(g => g.count() > 1); 

but there column, "asof" want rid of 1 of duplicate dts based on "asof" value, ever asof date newest.

i can think of loop able creating array of duplicates, finding newest asof, , removing others db table value. however, feel linq has ability able that, possibly comparator. have basic knowledge on it.

any ideas?

unless really need modify original datatable, create projection give records in each dt group has "newest" asof value:

  var rows = dt.asenumerable()                .orderby(row => row.field<sqldatetime>("asof"))                .groupby(row => row.field<sqldatetime>("dt"))                .select(rg => rg.first())                .tolist(); 

then either clear original data table , replace these rows or create new datatable based on these rows , swap original.

another option filter data before it's loaded data table, since didn't specify how happens can't offer guidance there.