将两个字典使用LINQ [英] Combine two Dictionaries with linq

问题描述

我有两本词典是这样的：

I have two dictionaries like this:

  var d1 = new Dictionary<string,object>();
  var d2 = new Dictionary<string,object>();

  d1["a"] = 1;
  d1["b"] = 2;
  d1["c"] = 3;

  d2["a"] = 11;
  d2["e"] = 12;
  d2["c"] = 13;

我想将它们合并成一个新的词典（在技术上，它并不必须是一个字典，它可能只是 KeyValuePairs 的序列），使得输出包含了所有的 KeyValuePairs 从D1只有从 D 2 的KeyValuePairs其键没有出现在 D 1 。

I would like to combine them into a new Dictionary (technically, it does not have to be a dictionary, it could just be a sequence of KeyValuePairs) such that the output contains all of the KeyValuePairs from d1 and only the KeyValuePairs from d2 whose Key does not appear in d1.

在概念上：

  var d3 = d1.Concat(d2.Except(d1))

但是，这是给从D1和D2的元素我的一切。

But that is giving me all of the elements from d1 and d2.

好像应该是显而易见的，但我一定是失去了一些东西。

Seems like it should be obvious, but I must be missing something.

推荐答案

在使用除了默认情况下它使用默认的相等比较，这对于 KeyValuePair <​​/ code>类型比较两个键和值。你可以这个方法来代替：

When you use Except by default it uses the default equality comparer, which for the KeyValuePair type compares both the keys and the values. You could this approach instead:

var d3 = d1.Concat(d2.Where(kvp => !d1.ContainsKey(kvp.Key)));

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