Hi!
I have excel file with 290000 records and columns count is 19.
I read it in datatable.
I have to get all records that are duplicated in columns index 0,1,5,6,8,9,16.
I use in List:
IDList = dt.AsEnumarable.Select(function(row) row(0)+“;”+row(1)+“;”+…+row(16)).ToList()
Then
IDDubl = IDList.Distinct().Where(function(item) IDList.LastIndexOf(item) <> IDList.IndexOf(item) ).ToList()
And then in for each I write comment in DT what is this double at each records in IDDubl
But it work very very long.
Could you please try the below query, this will only give the duplicate records from the columns
(From g In YourDt
Group g By a1=g(“ColumnName\Index”).tostring.trim, a2=g(“ColumnName\Index”).tostring.trim Into grp=Group
Where grp.count > 1
Select grp.tolist).selectmany(Function (x) x).copytodatatable
Feel free add as many columns you want in the query.
Thank’s! Yes it works fast.
But next problem its update column Comment in DT with 290000 records.
I find 440 dublicate and in for each row in DT I do LINQ Select from dt_dubl and if find record I update column Comment.
But it work very very long too.