Join collections by id with linq

Question

I have a object collection

var myData = new[]
{
    new {
        ID = "1285",
        COUNT = 45
    },
    new {
        ID = "1286",
        COUNT = 156
    },
    new {
        ID = "1287",
        COUNT = 965
    }
};

And my another collection comes from another data source like this:

var incomingData = new[]
{
    new {
        ID = "1285",
        LOCATION = "City-1"
    },
    new {
        ID = "1286",
        LOCATION = "City-2"
    },
    new {
        ID = "1287",
        LOCATION = "City-3"
    }
};

I want to change incoming data with COUNT property by Id.

var NewData = new[]
{
    new {
        ID = "1285",
        LOCATION = "City-1",
        COUNT = 45
    },
    new {
        ID = "1286",
        LOCATION = "City-2",
        COUNT = 156
    },
    new {
        ID = "1287",
        LOCATION = "City-3",
        COUNT = 965
    }
};

How can I do this with linq labda functions. I do not want to use foreach loop. (myData and incomingData collection lengths may be different)

If the collections are of differing lengths, what should happen to elements from one collection that don't appear in the other? — Matt Hogan-Jones, Jun 15 '17 at 13:48

score 4 · Answer 1 · answered Jun 15 '17 at 13:51

4

Just use ordinary join statements like this:

var result= 
    (
        from data in myData
        join inData in incomingData
            on data.ID equals inData.ID
        select new
        {
            data.ID,
            inData.LOCATION,
            data.COUNT
        }
    ).ToList();

Easy, simple, readable

answered Jun 15 '17 at 13:51

Arion

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"Easy, simple, readable" - very! – Jun 15 '17 at 13:52

Join collections by id with linq

1 Answers1