Convert an IOrderedEnumerable<KeyValuePair<string, int>> into a Dictionary<string, int>
我在跟踪另一个问题的答案,我得到:
1 2 3 4 5 6 7 8 | // itemCounter is a Dictionary<string, int>, and I only want to keep // key/value pairs with the top maxAllowed values if (itemCounter.Count > maxAllowed) { IEnumerable<KeyValuePair<string, int>> sortedDict = from entry in itemCounter orderby entry.Value descending select entry; sortedDict = sortedDict.Take(maxAllowed); itemCounter = sortedDict.ToDictionary<string, int>(/* what do I do here? */); } |
Visual Studio正在请求参数
'System.Collections.Generic.IEnumerable >'
does not contain a definition for 'ToDictionary' and the best
extension method overload
'System.Linq.Enumerable.ToDictionary has some invalid arguments(System.Collections.Generic.IEnumerable ,
System.Func)'
指定的泛型参数不正确。你是说源是字符串,而实际上它是一个键值对。
这个是正确的:
1 | sortedDict.ToDictionary<KeyValuePair<string, int>, string, int>(pair => pair.Key, pair => pair.Value); |
短版本为:
1 | sortedDict.ToDictionary(pair => pair.Key, pair => pair.Value); |
我相信两种方法结合起来最干净的方法是:对字典进行排序并将其转换回字典:
1 | itemCounter = itemCounter.OrderBy(i => i.Value).ToDictionary(i => i.Key, i => i.Value); |
这个问题太老了,但仍想给出答案供参考:
1 | itemCounter = itemCounter.Take(maxAllowed).OrderByDescending(i => i.Value).ToDictionary(i => i.Key, i => i.Value); |