C# 获取包含值 x 的字典中的所有键
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Get all keys in Dictionary containing value x
提问by Elmo
I have this:
我有这个：
Dictionary<integer, string> dict = new Dictionary<integer, string>();
I want to select all the items in the dictionary that contain the value abc.
我想选择字典中包含 value 的所有项目abc。
Is there an inbuilt function that lets me do this easily?
是否有内置功能可以让我轻松完成此操作？
采纳答案by Jon Skeet
Well it's reasonablysimple with LINQ:
嗯，使用 LINQ相当简单：
var matches = dict.Where(pair => pair.Value == "abc")
.Select(pair => pair.Key);
Note that this won't be even slightly efficient - it's an O(N)operation, as it needs to check every entry.
请注意，这甚至不会有点效率 - 这是一个O(N)操作，因为它需要检查每个条目。
If you need to do this frequently, you may want to consider using another data structure - Dictionary<,>is specifically designed for fast lookups by key.
如果您需要经常执行此操作，您可能需要考虑使用另一种数据结构 -Dictionary<,>专为通过 key进行快速查找而设计。
回答by Leonardo
Built-in function? No sorry... but another (not so beautiful) way is to iterate using foreach(KeyValuePair<integer, string> ...
内置功能？不抱歉......但是另一种（不太漂亮）的方法是使用foreach(KeyValuePair<integer, string> ...
