How to concat common rows in excel file and and write into single cell

This case we would do with grouping the data

prepare a target datatable - dtTarget
Assign Acitvity
LHS: dtTarget | datatype: DataTable
RHS: YourOriginDataTable.Clone

Assign Activity:
LHS: dtTarget
RHS:

(From d In YourOriginDataTable.AsEnumerable
Group d By k1=d(“Date”).toString.Trim, k2=d(“City”).toString.Trim Into grp=Group
Let nj= String.Join(",", grp.Select(Function (n) n(“Numbers”).toString.Trim))
Let ra = New Object(){k1,k2, nj}
Select r = dtTarget.Rows.Add(ra)).CopyToDataTable