Linq合并列表 [英] Linq Merge lists

问题描述

我的课:

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

我有IEnumerable<Foo>.我想按A进行List<Foo>分组，并获得Bars列表，该列表包含Bars中所有要分组的元素.

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.

所以最终的Foo.Bars应该包含Bar在组中的所有元素

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

linq可以吗?

推荐答案

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

如Rawling所述，它不会返回IEnumerable<Foo>，因此请尝试以下操作:

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()
            });

我不确定您是否想要Bars的独特列表.请注意，您可能需要覆盖类Bar中的Equals和GetHashCode.

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.

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