Linq query having group by

Question

RowNum IMAGEID SCANEDATE COUNT 1 10000131 2012-07-04 00:00:00.000 1 2 10002626 2012-08-03 00:00:00.000 1 3 10003348 2012-09-06 00:00:00.000 1 4 10003589 2012-09-15 00:00:00.000 8 5 10003590 2012-05-15 00:00:00.000 8 6 10003591 2012-04-15 00:00:00.000 8 7 10003592 2012-03-15 00:00:00.000 8 8 10003595 2012-02-15 00:00:00.000 8 9 10003596 2012-09-15 00:00:00.000 8 10 10003598 2012-09-15 00:00:00.000 8 11 10003599 2012-09-15 00:00:00.000 8

I have above datatable on which I need to apply linq query for getting result as follows

1) All images ids having same date should be listed in same cell(, seperated), and the count column should have the count of each date's respective no. of image ids

 Scan Date Image ID Count 11/27/2007 1001529,1001530,1001531,1001532,1001533,1001534,1001537,1001538,1001539,1001540,1001542 11 11/20/2008 1002501,1002502,1002503,1002504,1002505,1002506,1002507,1002508,1002509,1002510,1002511,1002512,1002513,1002514,1002515,1002516,1002517,1002518,1002519,1002520, 20 7/5/2011 1015237,1015238 2 7/6/2011 1015248,1015249,1015259,1015260,1015286,1015287,1015288,1015289,1015290,1015291,1015292,1015293,1015294,1015295,1015296,1015297,1015347,1015348,1015358,1015359, 32 1015370,1015371,1015381,1015382,1015396,1015397,1015410,1015411,1015412,1015413,1015429,1015430 7/7/2011 1015444,1015445 2

Please provide me the query for doing the above.

Sergey Berezovskiy · Accepted Answer · 2014-01-30 11:48:29Z

Group table rows by SCANEDATE field. Then project each group of rows by selecting scan date (key of group), joining all images ids into string, and getting count of rows in a group:

table.AsEnumerable() .GroupBy(r => r.Field<DateTime>("SCANEDATE")) .Select(g => new { ScanDate = g.Key, Ids = String.Join(",", g.Select(r => r.Field<int>("IIMAGEID"))), Count = g.Count() });

@user2783853 sorry, there was typo in lambda goes to operator. It should be g => new {.. instead of g = new { ...

sourabh devpura · Accepted Answer · 2014-01-30 11:25:07Z

var results = from p in tabel group p.IMAGEID by p.SCANEDATE into g select new { SCANEDATE = g.Key, IMAGEID = g.ToList() };

Or as a non-query expression:

var results = tabel.GroupBy(p => p.SCANEDATE , p => p.IMAGEID , (key, g) => new { SCANEDATE = key, IMAGEID = g.ToList() });

Basically the contents of the group (when view as an IEnumerable<T>) is a sequence of whatever values were in the projection (p.car in this case) present for the given key.

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