问题描述
假设我有 LINQ 查询，例如:
Say that I have LINQ query such as:
var authors = from x in authorsList
where x.firstname == "Bob"
select x;
鉴于 authorsList 是 List 类型，我如何从 authorsListAuthor 元素> 由查询返回到 authors?
Given that authorsList is of type List<Author>, how can I delete the Author elements from authorsList that are returned by the query into authors?
或者，换一种说法，如何从 authorsList 中删除所有与 Bob 相同的名字?
Or, put another way, how can I delete all of the firstname's equalling Bob from authorsList?
注意:为了问题的目的，这是一个简化的示例.
Note: This is a simplified example for the purposes of the question.
推荐答案
好吧，首先排除它们会更容易:
Well, it would be easier to exclude them in the first place:
authorsList = authorsList.Where(x => x.FirstName != "Bob").ToList();
但是，这只会更改 authorsList 的值，而不是从以前的集合中删除作者.或者，您可以使用 RemoveAll:
However, that would just change the value of authorsList instead of removing the authors from the previous collection. Alternatively, you can use RemoveAll:
authorsList.RemoveAll(x => x.FirstName == "Bob");
如果你真的需要基于另一个集合来做，我会使用 HashSet、RemoveAll 和 Contains:
If you really need to do it based on another collection, I'd use a HashSet, RemoveAll and Contains:
var setToRemove = new HashSet<Author>(authors);
authorsList.RemoveAll(x => setToRemove.Contains(x));
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