System.Collections.Immutable 10.0.0-preview.1.25080.5

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
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
7
Microsoft.CodeAnalysis.Workspaces.Common
A shared package used by the .NET Compiler Platform ("Roslyn") including support for analyzing projects and solutions. 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/6c4a46a31302167b425d5e0a31ea83c9a9aa1d09.
7
Microsoft.Build.Tasks.Core
This package contains the Microsoft.Build.Tasks assembly which implements the commonly used tasks of MSBuild.
6
Microsoft.Build.Framework
This package contains the Microsoft.Build.Framework assembly which is a common assembly used by other MSBuild assemblies.
6
Microsoft.CodeAnalysis.Workspaces.MSBuild
.NET Compiler Platform ("Roslyn") support for analyzing MSBuild projects and solutions. This should be used with at least one of the following packages to add the appropriate language support: - Microsoft.CodeAnalysis.CSharp.Workspaces - Microsoft.CodeAnalysis.VisualBasic.Workspaces More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/6c4a46a31302167b425d5e0a31ea83c9a9aa1d09.
6
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
5
Microsoft.CodeAnalysis.CSharp.Workspaces
.NET Compiler Platform ("Roslyn") support for analyzing C# projects and solutions. More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/6c4a46a31302167b425d5e0a31ea83c9a9aa1d09.
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Microsoft.CodeAnalysis.CSharp
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5
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/6c4a46a31302167b425d5e0a31ea83c9a9aa1d09.
4
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4
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Common utilities and interfaces for all NuGet libraries.
3
Microsoft.Extensions.Telemetry
Provides canonical implementations of telemetry abstractions.
3
NuGet.Common
Common utilities and interfaces for all NuGet libraries.
2
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/b9fb1610c87cccc8ceb74a770dba261a58e39c4a.
2
Json.More.Net
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2
Humanizer.Core
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2
Microsoft.Build
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2
Microsoft.EntityFrameworkCore
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Microsoft.CodeAnalysis.Common
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2

.NET Framework 4.6.2

.NET 8.0

  • No dependencies.

.NET 9.0

  • No dependencies.

.NET 10.0

  • No dependencies.

.NET Standard 2.0

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10.0.0-rc.1.25451.107 2 12/04/2025
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10.0.0-preview.6.25358.103 0 07/15/2025
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9.0.0-rc.2.24473.5 1 12/06/2025
9.0.0-rc.1.24431.7 1 12/06/2025
9.0.0-preview.7.24405.7 0 08/13/2024
9.0.0-preview.6.24327.7 0 07/09/2024
9.0.0-preview.5.24306.7 0 06/11/2024
9.0.0-preview.4.24266.19 1 12/04/2025
9.0.0-preview.3.24172.9 1 12/04/2025
9.0.0-preview.2.24128.5 0 03/12/2024
9.0.0-preview.1.24080.9 0 02/13/2024
8.0.0 1 12/05/2025
8.0.0-rc.2.23479.6 0 10/10/2023
8.0.0-rc.1.23419.4 1 12/06/2025
8.0.0-preview.7.23375.6 0 08/08/2023
8.0.0-preview.6.23329.7 1 12/04/2025
8.0.0-preview.5.23280.8 1 12/05/2025
8.0.0-preview.4.23259.5 0 05/16/2023
8.0.0-preview.3.23174.8 1 12/04/2025
8.0.0-preview.2.23128.3 0 03/14/2023
8.0.0-preview.1.23110.8 1 12/05/2025
7.0.0 1 12/05/2025
7.0.0-rc.2.22472.3 2 12/05/2025
7.0.0-rc.1.22426.10 1 12/05/2025
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7.0.0-preview.6.22324.4 0 07/12/2022
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6.0.1 1 12/05/2025
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6.0.0-rc.2.21480.5 1 12/04/2025
6.0.0-rc.1.21451.13 0 09/14/2021
6.0.0-preview.7.21377.19 1 12/04/2025
6.0.0-preview.6.21352.12 0 07/14/2021
6.0.0-preview.5.21301.5 0 06/15/2021
6.0.0-preview.4.21253.7 0 05/24/2021
6.0.0-preview.3.21201.4 0 04/08/2021
6.0.0-preview.2.21154.6 0 03/11/2021
6.0.0-preview.1.21102.12 2 12/05/2025
5.0.0 1 12/05/2025
5.0.0-rc.2.20475.5 0 10/13/2020
5.0.0-rc.1.20451.14 0 09/14/2020
5.0.0-preview.8.20407.11 0 08/25/2020
5.0.0-preview.7.20364.11 0 07/21/2020
5.0.0-preview.6.20305.6 0 06/25/2020
5.0.0-preview.5.20278.1 0 06/10/2020
5.0.0-preview.4.20251.6 0 05/18/2020
5.0.0-preview.3.20214.6 0 04/23/2020
5.0.0-preview.2.20160.6 0 04/02/2020
5.0.0-preview.1.20120.5 0 03/16/2020
1.7.1 1 12/05/2025
1.7.0 1 12/05/2025
1.7.0-preview3.19551.4 1 12/05/2025
1.7.0-preview2.19523.17 1 12/05/2025
1.7.0-preview1.19504.10 0 10/15/2019
1.6.0 1 12/05/2025
1.6.0-rc1.19456.4 0 09/16/2019
1.6.0-preview9.19421.4 1 12/06/2025
1.6.0-preview9.19416.11 1 12/05/2025
1.6.0-preview8.19405.3 1 12/05/2025
1.6.0-preview7.19362.9 1 12/05/2025
1.6.0-preview6.19303.8 1 12/05/2025
1.6.0-preview6.19264.9 1 12/05/2025
1.6.0-preview5.19224.8 1 12/05/2025
1.6.0-preview4.19212.13 1 12/05/2025
1.6.0-preview3.19128.7 1 12/05/2025
1.6.0-preview.19073.11 0 01/29/2019
1.6.0-preview.18571.3 0 12/03/2018
1.5.0 1 12/05/2025
1.5.0-rc1 0 05/06/2018
1.5.0-preview2-26406-04 1 12/05/2025
1.5.0-preview1-26216-02 1 12/06/2025
1.4.0 1 12/05/2025
1.4.0-preview2-25405-01 1 12/05/2025
1.4.0-preview1-25305-02 1 12/05/2025
1.3.1 1 12/05/2025
1.3.0 0 11/15/2016
1.3.0-preview1-24530-04 1 12/05/2025
1.2.0 1 12/05/2025
1.2.0-rc2-24027 0 05/16/2016
1.1.38-beta-23516 0 11/18/2015
1.1.38-beta-23409 1 12/05/2025
1.1.38-beta-23225 0 09/01/2015
1.1.37 0 07/29/2015
1.1.37-beta-23109 0 07/27/2015
1.1.37-beta-23019 0 06/30/2015
1.1.36 0 05/11/2015
1.1.34-rc 0 03/06/2015
1.1.33-beta 0 12/10/2014
1.1.32-beta 0 10/10/2014