LINQ Group by and String.Join

Question

_{Monday, November 27, 2017 7:14 AM}

I have a LINQ of

var holeinfo = (from h in context.HOLELOCATIONs
                                from d in context.DRILLHOLEDIAMDETAILS
                                where h.HOLEID == holeId && h.HOLEID == d.HOLEID && d.NAME == "rig_id"
                                select new
                                {
                                    holeid = h.HOLEID,
                                    startdate = h.STARTDATE,
                                    enddate = h.ENDDATE,
                                    depth = h.DEPTH,
                                    rigid = d.VALUE
                                })

This return data like

"AAA", 2017-11-01, 2017-11-02, 25, "RIG 1"
"AAA", 2017-11-01, 2017-11-02, 25, "RIG 2"

I would like to return "AAA", , 2017-11-01, 2017-11-02, 25, "RIG 1 | Rig 2" but I am having major issues getting it to group and String.Join(" | ", rigid)

Thanks

All replies (2)

_{Monday, November 27, 2017 9:05 AM ✅Answered}

Hi Quentin.Samuelson,

According to your description, I create a simple, which use LINQ gourp and c# method named string.Join as below for your reference.

string holeId = "AAA";
using (var context = new EFDemoContext())
{
                var holeinfo = (from h in context.HOLELOCATIONs
                                from d in context.DRILLHOLEDIAMDETAILs
                                where h.HOLEID == holeId && h.HOLEID == d.HOLEID && d.NAME == "rig_id"
                                select new
                                {
                                    holeid = h.HOLEID,
                                    startdate = h.STARTDATE,
                                    enddate = h.ENDDATE,
                                    depth = h.DEPTH,
                                    rigid = d.VALUE
                                });

                var result = holeinfo.ToList().GroupBy(t => new { t.holeid, t.startdate, t.enddate, t.depth }).Select(t => new
                {
                    holeid = t.Key.holeid,
                    startdate = t.Key.startdate,
                    enddate = t.Key.enddate,
                    depth = t.Key.depth,
                    rigid = string.Join("|",t.Select(x=>x.rigid))
}).ToList();

Best regards,

Zhanglong Wu

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_{Monday, November 27, 2017 10:57 PM}

Thanks Zhanglong,

I needed only one copy of the String so I added a Distinct.

string.Join("|", t.Select(x => x.rigid).Distinct())}).ToList();

Regards

Quentin