Group and aggregate a list of objects

Question

I have a list of data structured like this:

Field1 Field2 Field3 1 1 "abc" 1 1 "def" 1 2 "123" 1 2 "456"

I want to be able to merge this data so I end up with a single record per Field1 & Field2 and with the Field3 data concatenated. So in the above case I would get:

Field1 Field2 Field3 1 1 "abcdef" 1 2 "123456"

I would like to use linq/query expressions for this.

Ben M · Accepted Answer · 2010-07-01 03:26:57Z

3

var query = from row in rows group row by new { row.Field1, row.Field2 } into g select new RowClass { Field1 = g.Key.Field1, Field2 = g.Key.Field2, Field3 = g.Aggregate( new StringBuilder(), (sb, grp_row) => sb.Append(grp_row.Field3)) .ToString() }

answered Jul 1, 2010 at 3:26

Ben M

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2 Comments

user380689 Over a year ago

Thanks! I didn't realise you could group on multiple fields. I was trying to do nested grouping and just getting a mess.

Ben M Over a year ago

Glad to help. I agree that it's not a very intuitive syntax.

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