Sort Dictionary based on keys

Question

I need to order a Dictionary in VB.net based off of the keys. The keys and values are all strings. The dictionary does not have a .Sort(). Is there a way to do this without having to write my own sorting algorithm?

I modified it to clarify that, but it was edited. I need to order the dictionary based off of they keys. — user489041, Oct 19 '11 at 17:43
No, see, you still didn't say what you mean by "order a dictionary." Telling me that you want it based off of the keys doesn't explain what it means to you to "order a dictionary." — jason, Oct 19 '11 at 17:48
@Jason I think that it is apparent that "order a dictionary" to me, in the context of this question, means I want to sort it. — user489041, Oct 19 '11 at 21:45
What does it to "sort" a dictionary to you? Do you want to mutate the dictionary in some way so that it's "sorted?" Do you want to produce just an ordering of the keys? Do you want to produce an ordering of the values? Do you want to produce an ordering of the key/value pairs? Do you want to produce an entirely new data structure that encapsulates the "sorting?" You see, you have the dictionary. The concept of "ordering" it is rather ambiguous, especially since the `Dictionary` structure in .NET doesn't preserve any ordering whatsoever. — jason, Oct 19 '11 at 22:36

score 19 · Accepted Answer · edited May 23 '17 at 12:25

19

SortedDictionary comes to mind, but it sorts only on the key.

Otherwise, this answer might help How do you sort a C# dictionary by value?.

edited May 23 '17 at 12:25

Community

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answered Oct 19 '11 at 17:41

LarsTech

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score 5 · Answer 2 · answered Oct 19 '11 at 18:00

5

Exactly in vb.net work this code:

        Dim myDict As New Dictionary(Of String, String)
        myDict.Add("one", 1)
        myDict.Add("four", 4)
        myDict.Add("two", 2)
        myDict.Add("three", 3)

        Dim sortedDict = (From entry In myDict Order By entry.Value Ascending).ToDictionary(Function(pair) pair.Key, Function(pair) pair.Value)

        For Each entry As KeyValuePair(Of String, String) In sortedDict
            Console.WriteLine(String.Format("{0,10} {1,10}", entry.Key, entry.Value))
        Next

answered Oct 19 '11 at 18:00

apros

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I think you wanted `Order By entry.Key` not `entry.Value` based on the OP's edits. – Jim Wooley Oct 19 '11 at 18:06
For entry.Key we can use SortedDictionary witout any LINQ expression – apros Oct 19 '11 at 18:17

score 4 · Answer 3 · answered Oct 19 '11 at 18:05

If you need to retain the underlying Dictionary and not use a SortedDictionary, you could use LINQ to return an IEnumerable based off of what ever criteria you need:

Dim sorted = From item In items
             Order By item.Key
             Select item.Value

The SortedDictionary would probably give more performance under repeated usage however as long as you didn't need to invert that sort at some point in the future.

Sort Dictionary based on keys

3 Answers3