ImmutableHashDictionary 1.0.0

.NET Standard 2.0
NuGet\Install-Package ImmutableHashDictionary -Version 1.0.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
dotnet add package ImmutableHashDictionary --version 1.0.0
<PackageReference Include="ImmutableHashDictionary" Version="1.0.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add ImmutableHashDictionary --version 1.0.0
#r "nuget: ImmutableHashDictionary, 1.0.0"
#r directive can be used in F# Interactive, C# scripting and .NET Interactive. Copy this into the interactive tool or source code of the script to reference the package.
// Install ImmutableHashDictionary as a Cake Addin
#addin nuget:?package=ImmutableHashDictionary&version=1.0.0

// Install ImmutableHashDictionary as a Cake Tool
#tool nuget:?package=ImmutableHashDictionary&version=1.0.0


An implementation of IImmutableDictionary<TKey, TValue> that maintains O(1) value lookup, at the cost of mutation performance.

A good choice when working with dictionaries that remain moderately small and/or that are accessed for reading far more frequently than for modification.

This package also includes an ImmutableHashDictionary static factory class and an ImmutableHashDictionary<TKey, TValue>.Builder class that provide API''s identical to the ImmutableDictionary and ImmutableDictionary<TKey, TValue>.Builder classes.

Targets .NET Standard 2.0.

C#8 (Nullable Reference Types) Compliant.


The following benchmarks demonstrate the performance advantages and disadvantages of the ImmutableHashDictionary<TKey, TValue> class over the Dictionary<TKey, TValue> and ImmutableDictionary<TKey, TValue> classes.

The performance of value lookup by key for ImmutableHashDictionary<TKey, TValue> is, as desired, on par with that of Dictionary<TKey, TValue> and far exceeds that of ImmutableDictionary<TKey, TValue>, even for very large collections.

The performance of single add and remove operations for ImmutableHashDictionary<TKey, TValue> is, as expected, comparable to that of ImmutableDictionary<TKey, TValue> for smaller collections, but does not scale well (O(N) vs O(log N)).

Interestingly, the performance of ranged add and remove operations for ImmutableHashDictionary<TKey, TValue> tends to far exceed that of ImmutableDictionary<TKey, TValue>, and tends to be comparable to that of Dictionary<TKey, TValue> suggesting that the performance costs of mutating an ImmutableHashDictionary can be mitigated by performing mutations in batches, as much as possible.

Product Versions
.NET net5.0 net5.0-windows net6.0 net6.0-android net6.0-ios net6.0-maccatalyst net6.0-macos net6.0-tvos net6.0-windows
.NET Core netcoreapp2.0 netcoreapp2.1 netcoreapp2.2 netcoreapp3.0 netcoreapp3.1
.NET Standard netstandard2.0 netstandard2.1
.NET Framework net461 net462 net463 net47 net471 net472 net48
MonoAndroid monoandroid
MonoMac monomac
MonoTouch monotouch
Tizen tizen40 tizen60
Xamarin.iOS xamarinios
Xamarin.Mac xamarinmac
Xamarin.TVOS xamarintvos
Xamarin.WatchOS xamarinwatchos
Compatible target framework(s)
Additional computed target framework(s)
Learn more about Target Frameworks and .NET Standard.

NuGet packages

This package is not used by any NuGet packages.

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Version Downloads Last updated
1.0.0 3,518 1/21/2019

Initial release.