CODEWITHSUNDEEP
c#linq
coson
coson

Reputation: 8659

LINQ newbie question for 2 dimensional set

I have a LINQ query that pulls ID values with integers:

var data = from s in BaseData
           select new { s.Roid, s.Tid};

? data.ToArray()
{<>f__AnonymousType0<int,int>[14]}
    [0]: { Roid = 2384, Tid = 1 }
    [1]: { Roid = 2384, Tid = 2 }
    [2]: { Roid = 2384, Tid = 3 }
    [3]: { Roid = 2385, Tid = 4 }
    [4]: { Roid = 2385, Tid = 5 }
    [5]: { Roid = 2385, Tid = 6 }
    [6]: { Roid = 2386, Tid = 1 }
    [7]: { Roid = 2386, Tid = 3 }
    [8]: { Roid = 2386, Tid = 6 }
    [9]: { Roid = 2386, Tid = 7 }
    [10]: { Roid = 2387, Tid = 1 }
    [11]: { Roid = 2387, Tid = 2 }
    [12]: { Roid = 2387, Tid = 4 }
    [13]: { Roid = 2387, Tid = 9 }

What I would like to do is to query the result set for an Roid and extract only the Tid values.

So I want to query data for Roid = 2387, which will return 1, 2, 4, 9 which I want to convert to an array.

Is something like this possible?

// ***Edit***
var items = data.ToArray().Where(s => s.RepairOrderId == 2387);
// gets me closer, but I still only want the Tid's
// ***Edit***

Upvotes: 2

Views: 92

Answers (2)

dplante
dplante

Reputation: 2449

Using query expression syntax, this can also be written as follows. This should still produce the same IL:

int desiredRepairOrderId = 2387;
var q = from e in data where e.Roid == desiredRepairOrderId select new {e.Tid};
var arrayOfResults = q.ToArray();

Upvotes: 0

dlev
dlev

Reputation: 48596

var tidsFromRoid = data.Where(x => x.Roid == 2387).Select(x => x.Tid);

This will return a subsequence that contains only pairs whose Roid == 2387, and then from that subsequence, it projects each element onto just its Tid.

Note that if you want this as an array, call .ToArray() after:

var arrayOfTids = tidsFromRoid.ToArray();

If you wanted to do this from the very beginning (since maybe you won't ever care about other Roids) then you make your original query:

var arrayOfTids = BaseData.Where(x => x.Roid == 2387).Select(x => x.Tid).ToArray();

Upvotes: 6

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