如何查找和使用LINQ集合中删除重复的对象？ [英] How to find and remove duplicate objects in a collection using LINQ?
问题描述
我有一个简单的类重presenting的对象。它有5个属性（日期，2位小数，整数，字符串）。我有一个集合类，来源于 CollectionBase的，这是一个容器类持有多个对象，从我的第一课。
I have a simple class representing an object. It has 5 properties (a date, 2 decimals, an integer and a string). I have a collection class, derived from CollectionBase, which is a container class for holding multiple objects from my first class.
我的问题是，我想删除重复的对象（如对象具有相同日期，相同的小数，同样的整数和相同的字符串）。有一个LINQ查询，我可以写找到并删除重复？或者找到他们最起码？
My question is, I want to remove duplicate objects (e.g. objects that have the same date, same decimals, same integers and same string). Is there a LINQ query I can write to find and remove duplicates? Or find them at the very least?
推荐答案
您可以通过删除重复的 分明 运营商。
You can remove duplicates using the Distinct operator.
有两个重载 - 一个使用默认的相等比较器为你的类型（这对于一个自定义类型会调用等于（）方法的类型）。第二个，您可以提供自己的相等比较。他们都返回的新序列的再presenting你原来的设定没有重复。 既不超载实际修改您最初的集合 - 它们都返回一个新的序列，排除重复
There are two overloads - one uses the default equality comparer for your type (which for a custom type will call the Equals() method on the type). The second allows you to supply your own equality comparer. They both return a new sequence representing your original set without duplicates. Neither overload actually modifies your initial collection - they both return a new sequence that excludes duplicates..
如果您只想找到重复的，你可以使用 GROUPBY 这样做的：
If you want to just find the duplicates, you can use GroupBy to do so:
var groupsWithDups = list.GroupBy( x => new { A = x.A, B = x.B, ... }, x => x )
.Where( g => g.Count() > 1 );
要由类似的删除重复的IList＆LT;＆GT; ，你可以这样做：
To remove duplicates from something like an IList<> you could do:
yourList.RemoveAll( yourList.Except( yourList.Distinct() ) );
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