使用 LINQ 跨多个属性查找重复项

Using LINQ to find duplicates across multiple properties(使用 LINQ 跨多个属性查找重复项)

问题描述

给定一个具有以下定义的类:

Given a class with the following definition:

public class MyTestClass
{
    public int ValueA { get; set; }
    public int ValueB { get; set; }
}

如何在 MyTestClass[] 数组中找到重复值?

How can duplicate values be found in a MyTestClass[] array?

例如，

MyTestClass[] items = new MyTestClass[3];
items[0] = new MyTestClass { ValueA = 1, ValueB = 1 };
items[1] = new MyTestClass { ValueA = 0, ValueB = 1 };
items[2] = new MyTestClass { ValueA = 1, ValueB = 1 };

包含重复项，因为有两个 MyTestClass 对象，其中 ValueA 和 ValueB 都 = 1

Contains a duplicate as there are two MyTestClass objects where ValueA and ValueB both = 1

推荐答案

您可以通过按 ValueA 和 ValueB 对元素进行分组来查找重复项.之后对它们进行计数，您会发现哪些是重复的.

You can find your duplicates by grouping your elements by ValueA and ValueB. Do a count on them afterwards and you will find which ones are duplicates.

这就是你隔离受骗者的方法:

This is how you would isolate the dupes :

var duplicates = items.GroupBy(i => new {i.ValueA, i.ValueB})
  .Where(g => g.Count() > 1)
  .Select(g => g.Key);

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