僅通過特定鍵的值相交字典的兩個列表C＃

Question

我有兩個不同長度的字典列表。兩個字典中的鍵都是相同的，值可能不一樣。

var A = List<Dictionary<string, object>>(); 
var B = List<Dictionary<string, object>>(); 

我想交叉的A和B基於它們包含的字典對象中的3個鍵的值。

對於例如：

var dict = new Dictionary<string,object>{{"W",val1},{"X",val2},{"Y",val3},{"Z",val4}} 

字典類似於上述被包含在列表中A和B有用於VAL1，VAL2，VAL3，VAL4變化值。如果鍵W，X，Y的值相等，我想交叉A和B，但我不關心Z中交點的值。有沒有辦法實現這個優雅？

用一個例子闡述：

A.add(new Dictionary<string,object>{{"W",123},{"X",456},{"Y",789},{"Z",103}}); 
    A.add(new Dictionary<string,object>{{"W",124},{"X",456},{"Y",789},{"Z",893}}); 
    A.add(new Dictionary<string,object>{{"W",123},{"X",456},{"Y",789},{"Z",134}}); 

    B.add(new Dictionary<string,object>{{"W",123},{"X",456},{"Y",789},{"Z",900}}); 
    B.add(new Dictionary<string,object>{{"W",124},{"X",456},{"Y",789},{"Z",893}}); 
    B.add(new Dictionary<string,object>{{"W",212},{"X",321},{"Y",789},{"Z",134}}); 

如果我做A.intersect（B），我想獲得以下列表後面，

{"W",123},{"X",456},{"Y",789},{"Z",103} 
{"W",123},{"X",456},{"Y",789},{"Z",900} 
{"W",124},{"X",456},{"Y",789},{"Z",893} 

Answer 1

這會給你一個IEnumerable：

var c=A.Select(a=>new {W=a[W],X=a[X],Y=a[Y]}) 
    .Intersect(B.Select(a=>new {W=a[W],X=a[X],Y=a[Y]})); 

或者，自己創建一個自定義的IEqualityComparer，然後你可以這樣做：

var c=A.Intersect(B,new MyComparer()); 

類似：

class MyComparer : IEqualityComparer<Dictionary<string,object>> 
{ 
    public bool Equals(Dictionary<string,object> b1, Dictionary<string,object> b2) 
    { 
     if (b2 == null && b1 == null) 
      return true; 
     else if (b1 == null || b2 == null) 
      return false; 
     else if(b1["W"]==b2["W"] && b1["X"]==b2["X"] && b1["X"]==b2["X"]) 
      return true; 
     else 
      return false; 
    } 

    public int GetHashCode(Dictionary<string,object> bx) 
    { 
     int hCode = bx["W"]^bx["X"]^bx["Y"]; 
     return hCode.GetHashCode(); 
    } 
}