How to get a key by its index in a dictionary?

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I have a dictionary which its keys are combination of several words (using join method)
I want to split them in a selected key. The selection is done by defining the index.
How can I refer to a key by its index?

What I have tried:

string text = music.Keys[2]
The code above cannot be compiled.

Posted 3-Feb-21 8:37am

Alex Dunlop

Updated 3-Feb-21 9:04am

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PIEBALDconsult 3-Feb-21 14:40pm

No, it doesn't work that way.
But you could also make a list or another Dictionary with the same values.
I often have to make several indices for some objects.

2 solutions

Solution 1

music.ElementAt(2).Key;

Posted 3-Feb-21 8:47am

RickZeeland

Updated 3-Feb-21 8:59am

v2

Comments

PIEBALDconsult 3-Feb-21 14:53pm

Not necessarily repeatable? Items in a Dictionary have no inherent order.

RickZeeland 3-Feb-21 15:03pm

You are probably right, but when it is done immediately after defining the dictionary it should work I think.

PIEBALDconsult 3-Feb-21 15:07pm

Maybe, but it's still better to maintain an additional index -- possibly derive a new type of Dictionary with that ability cooked in.

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OriginalGriff · Accepted Answer · 2021-02-03T09:04:00

Indexes and Dictionaries aren't really much use: they aren't stored by any useful order, but by hash value. If you look at the source code: Reference Source[^]
and the Insert method (which Add calls) all indexing is done via a hashcode, which will not have any direct relation to the strings you are using as keys.

What I'd suggest is that you think of a different way to either store them, or access them - because even if you get code that works, you are setting yourself up for unpredictable and inconsistent results in the "real world".