Explain the difference set, intersection set and union set of complex type set in detail.Net

Preface

As the title says , stay

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Application development , When comparing two sets   We use Microsoft IEnumerable Packaged  

Except/Intersect/Union 

take   Difference set / intersection / Combine   The method is very convenient ; But for those who are not familiar with it , When encountering the request, include the reference type ( It doesn't contain string) When I gather, I feel very distressed ; Next, I will take you to learn how to get it through Microsoft's own method ** A collection of complex types ** The difference between the set 、 intersection 、 Combine .

scene

Here is the scene , I have the following two students .

Generate two entity sets ;

Now let's take the intersection / Difference set / Combine

Complete call example (.NET Core)：

　　

A closer look at the above output is obviously wrong , This involves complex type comparison , Please look at the code. ：

Normal class we declare

Because we want to compare reference types , Because in contrast, divide string Outside the reference type ,

By default, the comparison of other reference types is the heap address of the comparison

, So we need to inherit an interface to implement a custom comparison scheme  

IEqualityComparer<T>

&nbsp; Generic interfaces are as follows ：（ Here we take age and name as the comparison conditions ）

After modifying the class, there is the most important point ： Is to modify the method of comparison （ It is equivalent to declaring a custom comparator to the method ）

So far, the comparison of reference types has been completed , The condition method of the comparator can be adjusted according to the demand , If there are shortcomings , I hope you can correct me more ！！！

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