System.Collections.Immutable 8.0.0

About

This package provides collections that are thread safe and guaranteed to never change their contents, also known as immutable collections. Like strings, any methods that perform modifications will not change the existing instance but instead return a new instance. For efficiency reasons, the implementation uses a sharing mechanism to ensure that newly created instances share as much data as possible with the previous instance while ensuring that operations have a predictable time complexity.

The System.Collections.Immutable library is built-in as part of the shared framework in .NET Runtime. The package can be installed when you need to use it in other target frameworks.

How to Use

using System.Collections.Immutable;

// Create immutable set of strings
ImmutableHashSet<string> colors = ImmutableHashSet.Create("Red", "Green", "Blue");

// Create a new set by adding and removing items from the original set
ImmutableHashSet<string> colorsModified = colors.Remove("Red").Add("Orange");

foreach (string s in colorsModified)
{
    Console.WriteLine(s);
}

/* Example output:
 Blue
 Green
 Orange
 */

Main Types

The main types provided by this library are:

  • System.Collections.Immutable.ImmutableArray
  • System.Collections.Immutable.ImmutableArray<T>
  • System.Collections.Immutable.ImmutableDictionary
  • System.Collections.Immutable.ImmutableDictionary<TKey,TValue>
  • System.Collections.Immutable.ImmutableHashSet
  • System.Collections.Immutable.ImmutableHashSet<T>
  • System.Collections.Immutable.ImmutableList
  • System.Collections.Immutable.ImmutableList<T>
  • System.Collections.Immutable.ImmutableQueue
  • System.Collections.Immutable.ImmutableQueue<T>
  • System.Collections.Immutable.ImmutableSortedDictionary
  • System.Collections.Immutable.ImmutableSortedDictionary<TKey,TValue>
  • System.Collections.Immutable.ImmutableSortedSet
  • System.Collections.Immutable.ImmutableSortedSet<T>
  • System.Collections.Immutable.ImmutableStack
  • System.Collections.Immutable.ImmutableStack<T>
  • System.Collections.Frozen.FrozenDictionary
  • System.Collections.Frozen.FrozenDictionary<TKey, TValue>
  • System.Collections.Frozen.FrozenSet
  • System.Collections.Frozen.FrozenSet<T>

Additional Documentation

Feedback & Contributing

System.Collections.Immutable is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.

Showing the top 20 packages that depend on System.Collections.Immutable.

Packages Downloads
Npgsql
Npgsql is the open source .NET data provider for PostgreSQL.
1,384
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader
1,360
Microsoft.CodeAnalysis.Common
A shared package used by the Microsoft .NET Compiler Platform ("Roslyn"). Do not install this package manually, it will be added as a prerequisite by other packages that require it. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/6a5a63bbc9f4449d9bd1e95a8f9624939c3ccdc3.
1,338
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader System.Reflection.Metadata.Ecma335.MetadataBuilder System.Reflection.PortableExecutable.PEBuilder System.Reflection.PortableExecutable.ManagedPEBuilder
1,330
System.Reflection.Metadata
This package provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. The metadata format is defined by the ECMA-335 - Common Language Infrastructure (CLI) specification. The System.Reflection.Metadata library is built-in as part of the shared framework in .NET Runtime. The package can be installed when you need to use it in other target frameworks.
1,291
Microsoft.CodeAnalysis.Common
A shared package used by the Microsoft .NET Compiler Platform ("Roslyn"). Do not install this package manually, it will be added as a prerequisite by other packages that require it. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/e595ee276d14e14bfb3eb323fb57f2aa668bddea
1,273
Npgsql
Npgsql is the open source .NET data provider for PostgreSQL.
1,268
Microsoft.ML.DataView
Contains the IDataView system which is a set of interfaces and components that provide efficient, compositional processing of schematized data for machine learning and advanced analytics applications.
1,205
Microsoft.ML
ML.NET is a cross-platform open-source machine learning framework which makes machine learning accessible to .NET developers.
1,192
HtmlSanitizer
Cleans HTML from constructs that can be used for cross-site scripting (XSS)
1,190
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
1,173
System.Reflection.MetadataLoadContext
Provides read-only reflection on assemblies in an isolated context with support for assemblies that target different processor architectures and runtimes. Using MetadataLoadContext enables you to inspect assemblies without loading them into the main execution context. Assemblies in MetadataLoadContext are treated only as metadata, that is, you can read information about their members, but cannot execute any code contained in them.
1,173
Microsoft.CodeAnalysis.Common
A shared package used by the Microsoft .NET Compiler Platform ("Roslyn"). Do not install this package manually, it will be added as a prerequisite by other packages that require it. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/81d9274600db701a8b08ed8af3fd6b00a775cc33.
1,149
Microsoft.CodeAnalysis.Common
A shared package used by the Microsoft .NET Compiler Platform ("Roslyn"). Do not install this package manually, it will be added as a prerequisite by other packages that require it. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/df45061e218c9b5813c5531bc06fb238a23e30f6.
1,127
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader System.Reflection.Metadata.Ecma335.MetadataBuilder System.Reflection.PortableExecutable.PEBuilder System.Reflection.PortableExecutable.ManagedPEBuilder When using NuGet 3.x this package requires at least version 3.4.
1,120
System.Reflection.Metadata
This packages provides a low-level .NET (ECMA-335) metadata reader and writer. It's geared for performance and is the ideal choice for building higher-level libraries that intend to provide their own object model, such as compilers. Commonly Used Types: System.Reflection.Metadata.MetadataReader System.Reflection.PortableExecutable.PEReader System.Reflection.Metadata.Ecma335.MetadataBuilder System.Reflection.PortableExecutable.PEBuilder System.Reflection.PortableExecutable.ManagedPEBuilder 30ab651fcb4354552bd4891619a0bdd81e0ebdbf When using NuGet 3.x this package requires at least version 3.4.
804
Npgsql
Npgsql is the open source .NET data provider for PostgreSQL.
79
EnCore.WebSocket
Package for simplify work with web sockets. It uses SocketIoClientDotNet under hood. USAGE: Provides abstract class WebSocketService which implements IWebSocketService interface. Intended for Core project type. You need to create your own child from service class and register it in core module by interface.
14
EnCore.WebSocket
Package for simplify work with web sockets. It uses SocketIoClientDotNet under hood. USAGE: Provides abstract class WebSocketService which implements IWebSocketService interface. Intended for Core project type. You need to create your own child from service class and register it in core module by interface.
13
EnCore.WebSocket
Package for simplify work with web sockets. It uses SocketIoClientDotNet under hood. USAGE: Provides abstract class WebSocketService which implements IWebSocketService interface. Intended for Core project type. You need to create your own child from service class and register it in core module by interface.
12

.NET Framework 4.6.2

.NET 6.0

.NET 7.0

  • No dependencies.

.NET 8.0

  • No dependencies.

.NET Standard 2.0

Version Downloads Last updated
8.0.0 1,313 05/09/2025
7.0.0 1,258 05/09/2025
6.0.0 1,370 05/09/2025
5.0.0 1,152 05/09/2025
1.5.0 1,179 05/09/2025
1.3.1 1,349 05/09/2025