System.Collections.Immutable 11.0.0

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
Microsoft.NETCore
Provides a set of packages that can be used when building portable libraries on .NETCore based platforms. \r\n TFS ID: 1599443, GitHub SHA: https://github.com/dotnet/corefx/tree/eede273a4dfabcea608621f5e1bbf8ad00584cfb
239
Microsoft.VisualStudio.Debugger.Contracts
Package containing extensibility contracts between the debugger and other Visual Studio components, such as language services.
228
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C#(.NET, .NET Core, Unity, Xamarin).
218
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
204
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
198
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C#(.NET, .NET Core, Unity, Xamarin).
197
Microsoft.Build.Tasks.Core
This package contains the Microsoft.Build.Tasks assembly which implements the commonly used tasks of MSBuild.
197
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C# (.NET Framework, .NET 6, Unity, Xamarin).
194
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
193
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C#(.NET, .NET Core, Unity, Xamarin).
193
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
192
Microsoft.VisualStudio.Web.CodeGeneration.Contracts
Contains interfaces for Project Model and messaging for scaffolding.
192
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
187
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
185
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
185
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
184
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C# (.NET Framework, .NET 6, Unity, Xamarin).
184
Microsoft.Build.Tasks.Core
This package contains the Microsoft.Build.Tasks assembly which implements the commonly used tasks of MSBuild.
183
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
183

.NET 10.0

  • No dependencies.

.NET 11.0

  • No dependencies.

.NET Framework 4.6.2

.NET Standard 2.0

Version Downloads Last updated
11.0.0 4 11/10/2026
11.0.0-rc.3.26522.148 17 10/25/2026
11.0.0-rc.2.26504.105 22 10/14/2026
11.0.0-rc.1.26425.128 26 9/10/2026
11.0.0-preview.7.26381.103 33 8/13/2026
11.0.0-preview.6.26359.118 38 7/18/2026
11.0.0-preview.5.26302.115 34 6/10/2026
11.0.0-preview.4.26230.115 47 5/13/2026
11.0.0-preview.3.26207.106 47 5/3/2026
11.0.0-preview.2.26159.112 40 3/12/2026
11.0.0-preview.1.26104.118 42 2/12/2026
10.0.15 4 11/10/2026
10.0.14 23 10/25/2026
10.0.13 24 10/14/2026
10.0.12 30 9/9/2026
10.0.11 30 8/13/2026
10.0.10 36 7/17/2026
10.0.9 34 6/9/2026
10.0.8 40 5/13/2026
10.0.7 38 5/3/2026
10.0.6 40 5/3/2026
10.0.5 48 3/12/2026
10.0.4 44 3/12/2026
10.0.3 42 2/12/2026
10.0.2 43 1/15/2026
10.0.1 62 12/10/2025
10.0.0 70 11/12/2025
10.0.0-rc.2.25502.107 82 10/15/2025
10.0.0-rc.1.25451.107 100 9/9/2025
10.0.0-preview.7.25380.108 82 8/12/2025
10.0.0-preview.6.25358.103 108 7/15/2025
10.0.0-preview.5.25277.114 93 6/7/2025
10.0.0-preview.4.25258.110 119 5/16/2025
10.0.0-preview.3.25171.5 101 4/13/2025
10.0.0-preview.2.25163.2 111 3/21/2025
10.0.0-preview.1.25080.5 123 2/26/2025
9.0.23 4 11/10/2026
9.0.22 23 10/25/2026
9.0.21 21 10/14/2026
9.0.20 26 9/10/2026
9.0.19 41 8/13/2026
9.0.18 34 7/17/2026
9.0.17 36 6/10/2026
9.0.16 47 5/13/2026
9.0.15 41 5/3/2026
9.0.14 42 3/12/2026
9.0.13 47 2/12/2026
9.0.12 41 1/15/2026
9.0.11 78 11/12/2025
9.0.10 85 10/15/2025
9.0.9 93 9/9/2025
9.0.8 108 8/5/2025
9.0.7 103 7/9/2025
9.0.6 114 6/12/2025
9.0.5 99 5/16/2025
9.0.4 124 4/13/2025
9.0.3 123 3/12/2025
9.0.2 120 2/17/2025
9.0.1 143 1/18/2025
9.0.0 132 11/14/2024
9.0.0-rc.2.24473.5 119 10/15/2024
9.0.0-rc.1.24431.7 130 9/12/2024
9.0.0-preview.7.24405.7 109 8/14/2024
9.0.0-preview.6.24327.7 133 7/10/2024
9.0.0-preview.5.24306.7 124 6/14/2024
9.0.0-preview.4.24266.19 125 6/4/2024
9.0.0-preview.3.24172.9 130 4/23/2024
9.0.0-preview.2.24128.5 129 3/16/2024
9.0.0-preview.1.24080.9 125 3/1/2024
8.0.0 164 11/15/2023
8.0.0-rc.2.23479.6 122 10/13/2023
8.0.0-rc.1.23419.4 174 9/22/2023
8.0.0-preview.7.23375.6 168 8/16/2023
8.0.0-preview.6.23329.7 120 7/30/2023
8.0.0-preview.5.23280.8 134 7/31/2023
8.0.0-preview.4.23259.5 136 8/1/2023
8.0.0-preview.3.23174.8 128 5/14/2023
8.0.0-preview.2.23128.3 132 3/29/2023
8.0.0-preview.1.23110.8 135 2/22/2023
7.0.0 138 12/4/2022
7.0.0-rc.2.22472.3 139 10/21/2022
7.0.0-rc.1.22426.10 130 9/15/2022
7.0.0-preview.7.22375.6 151 9/15/2022
7.0.0-preview.6.22324.4 121 9/15/2022
7.0.0-preview.5.22301.12 134 6/27/2022
7.0.0-preview.4.22229.4 136 6/28/2022
7.0.0-preview.3.22175.4 145 6/28/2022
7.0.0-preview.2.22152.2 131 6/28/2022
7.0.0-preview.1.22076.8 111 6/28/2022
6.0.2-mauipre.1.22102.15 139 6/28/2022
6.0.2-mauipre.1.22054.8 139 6/28/2022
6.0.1 117 11/13/2024
6.0.0 161 6/28/2022
6.0.0-rc.2.21480.5 131 6/28/2022
6.0.0-rc.1.21451.13 132 6/28/2022
6.0.0-preview.7.21377.19 128 6/28/2022
6.0.0-preview.6.21352.12 152 6/28/2022
6.0.0-preview.5.21301.5 143 6/28/2022
6.0.0-preview.4.21253.7 135 6/28/2022
6.0.0-preview.3.21201.4 157 6/28/2022
6.0.0-preview.2.21154.6 118 6/28/2022
6.0.0-preview.1.21102.12 138 6/28/2022
5.0.0 138 6/28/2022
5.0.0-rc.2.20475.5 133 6/28/2022
5.0.0-rc.1.20451.14 148 6/28/2022
5.0.0-preview.8.20407.11 139 6/28/2022
5.0.0-preview.7.20364.11 120 6/28/2022
5.0.0-preview.6.20305.6 122 6/28/2022
5.0.0-preview.5.20278.1 147 6/28/2022
5.0.0-preview.4.20251.6 128 6/28/2022
5.0.0-preview.3.20214.6 149 6/28/2022
5.0.0-preview.2.20160.6 126 6/28/2022
5.0.0-preview.1.20120.5 160 6/28/2022
1.7.1 135 6/28/2022
1.7.0 154 6/28/2022
1.7.0-preview3.19551.4 138 6/28/2022
1.7.0-preview2.19523.17 151 6/28/2022
1.7.0-preview1.19504.10 123 6/28/2022
1.6.0 137 6/28/2022
1.6.0-rc1.19456.4 136 6/28/2022
1.6.0-preview9.19421.4 147 6/28/2022
1.6.0-preview9.19416.11 125 6/28/2022
1.6.0-preview8.19405.3 139 6/28/2022
1.6.0-preview7.19362.9 128 6/28/2022
1.6.0-preview6.19303.8 149 6/28/2022
1.6.0-preview6.19264.9 132 6/28/2022
1.6.0-preview5.19224.8 174 6/28/2022
1.6.0-preview4.19212.13 150 6/28/2022
1.6.0-preview3.19128.7 132 6/28/2022
1.6.0-preview.19073.11 123 6/28/2022
1.6.0-preview.18571.3 153 6/28/2022
1.5.0 167 6/28/2022
1.5.0-rc1 124 6/28/2022
1.5.0-preview2-26406-04 141 6/28/2022
1.5.0-preview1-26216-02 126 6/28/2022
1.4.0 158 6/28/2022
1.4.0-preview2-25405-01 141 6/28/2022
1.4.0-preview1-25305-02 121 6/28/2022
1.3.1 166 6/28/2022
1.3.0 143 6/28/2022
1.3.0-preview1-24530-04 133 6/28/2022
1.2.0 137 6/28/2022
1.2.0-rc2-24027 132 6/28/2022
1.1.38-beta-23516 120 6/28/2022
1.1.38-beta-23409 145 6/28/2022
1.1.38-beta-23225 149 6/28/2022
1.1.37 151 6/28/2022
1.1.37-beta-23109 150 6/28/2022
1.1.37-beta-23019 144 6/28/2022
1.1.36 143 6/28/2022
1.1.34-rc 138 6/28/2022
1.1.33-beta 128 6/28/2022
1.1.32-beta 140 6/28/2022