如何获得List< T>中元素的索引.在C#中 [英] How to get the index of element in the List<T> in c#

问题描述

我有一个列表，其中包含一些元素，例如A B CD.我想获取B的索引.我如何得到它?

I have a list who have some element like A B C D. I want to get the index of B. How i can get it?

我想用C#做到这一点.

I want to do this in C#.

推荐答案

此可以很简单:

int index = list.IndexOf(b);

其中 b 是要查找的东西，但是在这里，关于相等性的定义存在歧义.默认情况下，类将使用引用相等.一个常见的错误是创建两个具有相同字段的类实例，并期望它们算作 equal .为此，您应该真正覆盖 Equals (并为相同的 T 理想地实现 IEquatable< T> ).如果覆盖 Equals ，还应该覆盖 GetHashCode 和理想地 == 和！=运算符.

where b is the thing to find, however there is an ambiguity here over the definition of equality. By default, classes will use reference-equality. A common mistake is creating two class instances that have identical fields, and expecting them to count as equal. To do this, you should really override Equals (and ideally implement IEquatable<T> for the same T). If you override Equals, you should also override GetHashCode, and ideally the == and != operators.

另一种选择是用谓词或比较器查找匹配项，这样可以避免所有工作

Another alternative is to find the match with a predicate or comparer, which can avoid all that work

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