如何比较两个词典 [英] How to compare two dictionaries

问题描述

我有一本词典使用

I have a dictionary Used

Dim Used As New Dictionary(Of Integer, Boolean)
111,true
5,true
125,true

我有第二本字典ByteDic

I have second dictionary ByteDic

Dim ByteDic As Dictionary(Of byte, Integer)
111,1233
22,334
125,123
10, 128

我想选择ByteDic的最大值，该密钥不包含二手（我想从ByteDic中选择334值）



我尝试过：

I want select max value of ByteDic that key not contain by Used (I want select 334 value from ByteDic)

What I have tried:

int MaxValue = ByteDic.Select(x => Used.Keys.ToList.IndexOf(x.Key) > -1).Max;

Dim MaxValue As Integer = ByteDic.Select(Function(x) Used.Keys.ToList.IndexOf(x.Key) > -1).Max

推荐答案

通过在比较中使用Select，您将只获得bool结果。你需要在 Where 语句中使用比较。



另外，使用 ToList 在Linq查询中， ToList 将被称为 ，用于每次 比较效率低下。因此，您最好使用包含列表的临时变量，以便只调用一次。



考虑到这一点，我建议使用类似的东西：

By using Select on a comparison, you will only get a bool result. You need to use the comparison in a Where statement.

Also, using ToList inside a Linq query, the ToList will be called for each comparison which is highly inefficient. So you wouild be better off using a temporary variable that contains the list so that it is only called once.

With that in mind, I would suggest using something like:

Dim result = ByteDic.Where(Function(x) Not used.Any(Function(y) y.Key.Equals(x.Key))).Max(Function(x) x.Value)

或

or

Dim result = ByteDic.Where(Function(x) Not used.Keys.Contains(x.Key)).Max(Function(x) x.Value)

或

or

Dim result = ByteDic.Where(Function(x) Not used.ContainsKey(x.Key)).Max(Function(x) x.Value)

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