How do I use Linq to group a DataTable by multiple rows/columns into a new datatable with duplicate rows concatenated?
You only need to group by the ID of the row. Then, concatenate all the values in each group: from row in passedInTable.AsEnumerable() group row by row. Field("ID") into rowGroup select new { ID = rowGroup.
Key, Val1 = String. Join(" ", rowGroup. Select(row => row.
Field("Val1")).ToArray()), Val2 = String. Join(" ", rowGroup. Select(row => row.
Field("Val2")).ToArray()), }.
Very cool. Grouping was the key, plus I was trying to use Linq's aggregate method which apparently wasn't necessary. Thank ya sir!
– Carter Feb 19 '10 at 0:35 Aggregate would work here, String. Join just happens to be a specific implementation we can leverage :-) – Bryan Watts Feb 19 '10 at 0:42 Yeah, that's what I gathered. Might try to aggregate it just to see if I can.
– Carter Feb 19 '10 at 0:48.
God, Linq confuses me... I've found quite a few examples that do similar things to what I need, but I'm still getting all turned around. I want to use Linq to build a table where essentially in GroupedTable the IDs would become unique and values for duplicated IDs get concatenated into their respective rows. We'll call it GroupedTable.
I think I could see how I could do what I need at this point with some for looping but I'm pretty sure it's do-able via Linq. Especially based on all the examples I see out there, using .sum() for number types. I guess the ultimate question is, in that query up above, how do I aggregate the values for the val1 and val2 columns from within that select new block so it's selecting out the concatenated values.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.
Related Questions
Binding primefaces dataTable with org.primefaces.component.datatable.DataTable?
How can I return all the columns of a table using multiple distinct columns in Linq?
Summation of multiple columns grouped by multiple columns in R and output results as data frame?
C# Linq Group By on multiple columns?
Group By Multiple Columns - LINQ?
Deleting MySQL rows that have two duplicate fields, but not a duplicate ID?