Dictionary creation

Hello Everyone.
I have a basic question.
Please help me with this dictionary.
Why does it come in random combinations? Why a letter “A” doesn’t correspond 101 ???

dont know why but the Lunchbox version of the node gives me this

Dictionaries are unorder collections. There are reasons why the order of items appears seemingly random; there is actually a logical reason why. This video explains how python builds dictionaries and orders key value pairs; I suspect under the hood, Dynamo is doing the same:


But key A does contain 101, just not as the first value of the dictionary :slight_smile:

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Dynamo is written in C#. We can take a look what’s under the hood of Dictionary.ByKeysValues node here:

So this node returns ImmutableDictionary object.

From https://docs.microsoft.com/pl-pl/dotnet/api/system.collections.immutable.immutabledictionary-2?view=netcore-2.2 we can learn that ImmutableDictionary is an immutable, unordered collection of keys and values.


I know. I was referring to the mechanics of how dictionaries are allocated memory addresses (hashing) - which that python video explains really well - demonstrating why dictionary key value pairs are seemingly ‘unordered’ and providing an insight and answer the OP if i am not mistaken. All languages which support dictionaries do the same thing, so the specific language in use isn’t important.


I wanted to post a general reply. Still, the node could behave as @m.shcheblykin expected because both C# and IronPython have ordered dictionary classes and they were not used here.


Saves on memory and CPU - order doesn’t matter as values are called for by name.

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Yes, my fault. Looks like I didn’t understand the main concept and purpose of these dictionaries

We’re all here to learn :point_right:

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