How to remove rows from a DataTable in C # with a filter?

Question

I have a DataTable with some rows, one of them is ID (row) and System.DateTime. other lines are not important now.

now I want to delete all rows with the same identifier that has an older date-date as the newest.

Is it possible?

here is an example

• ID: 123 Date: 12/24/2010 ...
• ID: 123 Date: 12/23/2010 ...
• ID: 123 Date: 12/22/2010 ...

after that I only want:

• ID: 123 Date: 12/24/2010 ...

Answer 1

Try the following

public void DeleteOldById(DataTable table, int id) { var rows = table.Rows.Cast<DataRow>().Where(x => (int)x["ID"] == id); DateTime specifyDate = rows.Max(x => (DateTime)x["Date"]) rows.Where(x =>(DateTime)x["Date"] < specifyDate).ToList(). ForEach(x => x.Delete()); } public void DeleteAllOldRows(DataTable table) { var ids = table.Rows.Cast<DataRow>().Select(x => (int)x["ID"]).Distinct(); foreach(int id in ids) DeleteOldById(table,id); }