Finding Index of Duplicate Entries using linq query

[yash.choursia]

Hi Team,
I have an excel which contains duplicate invoice numbers but is sorted in ascending order, so i need to capture the starting index and ending index with respect to the invoice number.
The input will be:

and the output will be like:

and so on.

[yash.choursia]

@Yoichi Please help.

[Yoichi]

Hi,

How about the following?

dtResult = dt.AsEnumerable.Select(Function(r,i) Tuple.Create(r,i+1)).GroupBy(Function(t) t.Item1.Item("InvoiceNo.").ToString).Select(Function(g) dtResult.LoadDataRow({g.Key,g.Min(Function(t) t.Item2),g.Max(Function(t) t.Item2)},False)).CopyToDataTable

Sample20230713-2aL.zip (7.8 KB)

[yash.choursia]

Thanks @Yoichi This helped me a lot.