不同类型的List找交集,该怎么解决

不同类型的List找交集

C# code

情况1:var pList1 = new List<Product>{    new Product {ID = 1, SubID = "AA", Price = 0.1 },    new Product {ID = 2, SubID = "BB", Price = 0.2 },    new Product {ID = 3, SubID = "BB", Price = 0.4 },    new Product {ID = 4, SubID = "AA", Price = 0.7 },    new Product {ID = 5, SubID = "CC", Price = 0.3 }};var pList2 = new List<SubProduct>{    new SubProduct { ID="AA" },    new SubProduct { ID="BB" }}情况2:var pList1 = new List<Product>{    new Product {ID = 1, SubID = "AA", Price = 0.1 },    new Product {ID = 2, SubID = "BB", Price = 0.2 },    new Product {ID = 3, SubID = "BB", Price = 0.4 },    new Product {ID = 4, SubID = "AA", Price = 0.7 }};var pList2 = new List<SubProduct>{    new SubProduct { ID="AA" },    new SubProduct { ID="BB" },    new SubProduct { ID="CC" }}

问题:
  1.情况1中pList1中有3个SubID,但是pList2中只有两个,所以pList1中的SubID="CC"为异常数据,需剔除.
  2.情况2中pList1中只有2个SubID,pList2中有三个,且pList2中的ID = "CC"的在pList1中的记录Count为零,需剔除.

现在用的最普通的内嵌循环, - -

C# code

IList<Product> tmpPList = new List<Product>();foreach(SubProduct sp in pList2){    var q = qList1.Where(s => s.SubID == sp.ID).Count() > 0    if (q.Any())    {        tmpPList.Add(q);    }       }//为什么要建立一个临时列表,因为后续要对这个列表进行重组,//现在的更改决定了后面的列表更新内容if(!tmpPList.Any()){    foreach(Product tp in tmpPList)    {        tmpList.Remove(tp);        //do something    }}

请教有效率高点的写法,因为实际应用中这两个List的数据量比较大.

[解决办法]

C# code

var pList1 = new List<Product>(){    new Product {ID = 1, SubID = "AA", Price = 0.1 },    new Product {ID = 2, SubID = "BB", Price = 0.2 },    new Product {ID = 3, SubID = "BB", Price = 0.4 },    new Product {ID = 4, SubID = "AA", Price = 0.7 }};var pList2 = new List<SubProduct>(){    new SubProduct { ID="AA" },    new SubProduct { ID="BB" },    new SubProduct { ID="CC" }};var result = pList1.Where(x => pList2.Select(y => y.ID).Contains(x.SubID)).ToList();
[解决办法]
var m_ilAllSelect = lstSource.Select(r => r.ID).AsEnumerable();//新选择的列表
///////下面开始处理了
List<int> m_ilNewSelect = m_ilAllSelect.ToList();//新选择列表
List<int> m_ilExcept = m_ilNewSelect.Except(m_mcuids).ToList(); //两者的不同之处
List<int> m_iExceptAfterAndNew = m_ilNewSelect.Except(m_ilExcept).ToList();//新选择列表与差集比较，则是新选择中的旧的
  http://www.cnblogs.com/greatverve/archive/2012/03/29/csharp-list-linq-Intersection.html
[解决办法]
IList<ItemsTOP> listTOP = new ServiceTOP().GetItemsTOP();

IList<Items> list = new WCFServiceClient().GetItems();

var filteredListTOP = listTOP.Select(i => new { ID = i.id, Name = i.Name} ).Except( i => i.IdTOP );

[解决办法]
来个快速的

C# code
var ids = pList2.Select(x => x.ID).Distinct().ToList();var result = pList1.GroupBy(x => x.SubID).Where(x => ids.Contains(x.Key)).SelectMany(x => x).ToList();
[解决办法]
如果你的电脑有多个处理器核，还可以更快（在一个四核处理器上大致能快3倍）：

C# code
var ids = pList2.Select(x => x.ID).Distinct().ToList();var result = pList1.AsParallel().GroupBy(x => x.SubID).Where(x => ids.Contains(x.Key)).SelectMany(x => x).ToList(); 
  

 

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