What's the fastest way to copy the values and keys from one dictionary into another in C#?
There's the Dictionary
constructor that takes another Dictionary
.
You'll have to cast it IDictionary
, but there is an Add()
overload that takes KeyValuePair<TKey, TValue>
. You're still using foreach, though.
There's nothing wrong with a for/foreach loop. That's all a hypothetical AddRange method would do anyway.
The only extra concern I'd have is with memory allocation behaviour, because adding a large number of entries could cause multiple reallocations and re-hashes. There's no way to increase the capacity of an existing Dictionary by a given amount. You might be better off allocating a new Dictionary with sufficient capacity for both current ones, but you'd still need a loop to load at least one of them.
var Animal = new Dictionary<string, string>();
one can pass existing animal Dictionary to the constructor.
Dictionary<string, string> NewAnimals = new Dictionary<string, string>(Animal);