How to convert IEnumerable of KeyValuePair<x, y> to Dictionary?

问题:

Is there streamlined to convert list/enumberable of KeyValuePair<T, U> to Dictionary<T, U>?

Linq transformation, .ToDictionary() extension did not work.

回答1:

.ToDictionary(kvp=>kvp.Key,kvp=>kvp.Value); 

Isn't that much more work.

回答2:

You can create your own extension method that would perform as you expect.

public static class KeyValuePairEnumerableExtensions {     public static Dictionary<TKey, TValue> ToDictionary<TKey, TValue>(this IEnumerable<KeyValuePair<TKey, TValue>> source)     {         return source.ToDictionary(item => item.Key, item => item.Value);     } } 

回答3:

This is the best I could produce:

public static IDictionary<TKey, TValue> ToDictionary<TKey, TValue>(IEnumerable<KeyValuePair<TKey, TValue>> keyValuePairs) {     var dict = new Dictionary<TKey, TValue>();     var dictAsIDictionary = (IDictionary<TKey, TValue>) dict;     foreach (var property in keyValuePairs)     {         (dictAsIDictionary).Add(property);     }     return dict; } 

I compared the speed of converting an IEnumerable of 20 million key value pairs to a Dictionary using Linq.ToDictionary with the speed of this one. This one ran in 80% of the time of the Linq version. So it's faster, but not a lot. I think you'd really need to value that 20% saving to make it worth using.

文章来源: How to convert IEnumerable of KeyValuePair to Dictionary?