问题描述
在大多数编程语言中,字典比哈希表更受欢迎.背后的原因是什么?
In most programming languages, dictionaries are preferred over hashtables. What are the reasons behind that?
推荐答案
就其价值而言,字典是(概念上)一个哈希表.
For what it's worth, a Dictionary is (conceptually) a hash table.
如果您的意思是为什么我们使用 Dictionary
类而不是 Hashtable
类?",那么答案很简单:Dictionary
是泛型类型,Hashtable
不是.这意味着您可以使用 Dictionary<TKey, TValue>
获得类型安全,因为您不能将任何随机对象插入其中,并且您不必强制转换取出的值.
If you meant "why do we use the Dictionary<TKey, TValue>
class instead of the Hashtable
class?", then it's an easy answer: Dictionary<TKey, TValue>
is a generic type, Hashtable
is not. That means you get type safety with Dictionary<TKey, TValue>
, because you can't insert any random object into it, and you don't have to cast the values you take out.
有趣的是,.NET Framework 中的 Dictionary
实现是基于 Hashtable
的,从源代码中的这条注释可以看出:
Interestingly, the Dictionary<TKey, TValue>
implementation in the .NET Framework is based on the Hashtable
, as you can tell from this comment in its source code:
通用字典是从 Hashtable 的源中复制的
The generic Dictionary was copied from Hashtable's source
来源
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