按键分组并使用LINQ将值发送到列表中

Question

假设我有一个简单的地址类,如下所示:

public class Address
{
    public int AddressId { get; set; }
    public List<int> NodeIds { get; set; }
}

并填写了如下地址列表:

List<Address> listOfAddresses = new List<Address> 
{
    new Address {AddressId=1, NodeIds=new List<int>{1}},
    new Address {AddressId=2, NodeIds=new List<int>{2}},
    new Address {AddressId=3, NodeIds=new List<int>{3}},
    new Address {AddressId=1, NodeIds=new List<int>{4}},
    new Address {AddressId=1, NodeIds=new List<int>{5}}
}

并且我想在AddressIds上进行分组,因此结果列表将具有基本上卷起的NodeId,以防重复如下:

listOfAddressesWithoutDupes = 
AddressId=1, NodeIds=List<int>{1,4,5},
AddressId=2, NodeIds=List<int>{2}},
AddressId=3, NodeIds=new List<int>{3}

所以基本上我正在寻找一个能让我超越结果的groupby函数(或其他东西)

List<Address> listOfFilteredAddresses = listOfAddresses.GroupBy(x=>x.AddressId).Select(y=>new Address{AddressId=y.Key, NodeIds=?});

提前致谢..

Answer 1

你快到了:

List<Address> listOfFilteredAddresses =
    listOfAddresses
    .GroupBy(x=>x.AddressId)
    .Select(y=>new Address{
        AddressId=y.Key
    ,   NodeIds=y.SelectMany(x=>x. NodeIds).ToList()
    });

这假设NodeIds在Address独特中; 如果不是,添加Distinct()后SelectMany.