ValueTuples是否适合用作字典键? [英] Are ValueTuples suitable as dictionary keys?
问题描述
我认为这可能是一本便捷的字典:
I'm thinking this could be a convenient dictionary:
var myDict = new Dictionary<(int, int), bool>();
散列是什么样的?
等效的密钥类型是什么(
What would the hashes look like?
What would the equivalent key type (struct) look like?
推荐答案
是的,很好。 ValueTuple< ...>
家族是一组定义良好的规则结构,它们具有正确的相等性和哈希码行为,可以用作字典键。有一个轻微警告,它们是可变的而不是不可变的,但是由于存在复制语义,因此在这种情况下并不会真正影响它们(这意味着:在拥有密钥之后,您不能再更改密钥了。已添加,因为您只更改了键的不同副本;这与可变类作为键的问题非常不同)。您可以在此处查看代码。
Yes, that's fine. The ValueTuple<...>
family is a well-defined set of regular structs with the correct equality and hash-code behaviour to work as dictionary keys. There is a slight caveat in that they are mutable rather than immutable, but that doesn't really impact them in this context thanks to copy semantics (which means: you can't change the key after it has been added, as you're only changing a different copy of the key; this is very different to the problem with mutable classes as keys). You can see the code here.
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