How to compare two dictionaries

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I have a dictionary Used

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

I have second dictionary ByteDic

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

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

Posted 6-Jul-18 13:04pm

gacar

Updated 7-Jul-18 19:33pm

v4

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Graeme_Grant · Accepted Answer · 2018-07-07T19:33:00

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:

VB

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

or

VB

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

or

VB

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