Question

I’m trying to use Linq to pivot a data table. Trawling through the responses here, and a few other sources I think I’ve managed to get most of the way there but I’m having a little trouble completing the query (entirely as a result of my lack of understanding of Linq, however I’m currently on a tight schedule). The data tables are as follows:

SOURCE:

   Name      |ItemCode|Rank
----------------------------      
   -1        |blah1   |1
   -1        |blah2   |2
   -1        |blah3   |3
   -1        |blah4   |4
*PLACEHOLDER*|blah2   |7
*PLACEHOLDER*|blah1   |22

DESIRED OUTPUT:

 ItemCode    |companyWide|myGroup
----------------------------      
   blah1     |1          |22
   blah2     |2          |7
   blah3     |3          |
   blah4     |4          |

The code I have currently is:

var temp = reportDataTable.AsEnumerable()
                           .GroupBy(a => a["ItemCode"]).Select(b => new{ItemCode = b.Key, 
                                                                        companyWide = b.Where(a => (string)a["Name"] == "-1").Select(a => a["Rank"]),
                                                                        myGroup = b.Where(a => (string)a["Name"] == "*PLACEHOLDER*").Select(a => a["Rank"]) }) ;

The grouping by ItemCode works, but I’m guessing my syntax is wrong in filling the other 2 columns. Any help with this would be greatly appreciated.

Answer 1

Added FirstOrDefault() to items:

var temp = reportDataTable.AsEnumerable().GroupBy(a => a["ItemCode"]).Select(b => 
    new{ItemCode = b.Key, 
        companyWide = b.Where(a => (string)a["Name"] == "-1").Select(a =>a["Rank"]).FirstOrDefault(),
        myGroup = b.Where(a => (string)a["Name"] == "*PLACEHOLDER*").Select(a => a["Rank"]).FirstOrDefault() }) ;