CODEWITHSUNDEEP
c#linq
Andrew Kalashnikov
Andrew Kalashnikov

Reputation: 3173

Linq Merge lists

My class:

    public class Foo
    {
        public int A { get; set; }
        public List<Bar> Bars { get; set; }
    }

I've got IEnumerable<Foo>. I would like get List<Foo> grouping by A, and get Bars list, which contais all elements at Bars for group.

So final Foo.Bars should contains all elements of Bar at group

Is it possible with linq?

Upvotes: 2

Views: 1028

Answers (1)

Tim Schmelter
Tim Schmelter

Reputation: 460288

var result = foos.GroupBy(f => f.A)
                 .SelectMany(grp => grp.Select(f => f.Bars));

As Rawling has mentioned, this returns not an IEnumerable<Foo>, so try this:

IEnumerable<Foo> result = 
            foos.GroupBy(f => f.A)
            .Select(grp => new Foo() { 
                A = grp.Key,
                Bars = grp.SelectMany(ff => ff.Bars).Distinct().ToList()
            });

I'm not sure whether you want a distinct list of Bars or not. Note that you may need to override Equals and GetHashCode in class Bar.

Upvotes: 5

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