System.Collections.Immutable 9.0.1

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
170
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C#(.NET, .NET Core, Unity, Xamarin).
157
Microsoft.VisualStudio.Debugger.Contracts
Package containing extensibility contracts between the debugger and other Visual Studio components, such as language services.
150
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
139
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C#(.NET, .NET Core, Unity, Xamarin).
137
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
136
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C#(.NET, .NET Core, Unity, Xamarin).
133
System.Diagnostics.StackTrace
Provides the System.Diagnostics.StackTrace class, which allows interaction with local and remote processes. Commonly Used Types: System.Diagnostics.StackFrame System.Diagnostics.StackTrace When using NuGet 3.x this package requires at least version 3.4.
129
Microsoft.Build.Tasks.Core
This package contains the Microsoft.Build.Tasks assembly which implements the commonly used tasks of MSBuild.
128
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C# (.NET Framework, .NET 6, Unity, Xamarin).
126
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
125
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C# (.NET Framework, .NET 6, Unity, Xamarin).
125
MessagePack
Extremely Fast MessagePack(MsgPack) Serializer for C# (.NET Framework, .NET 6, Unity, Xamarin).
124
Microsoft.VisualStudio.Web.CodeGeneration.Contracts
Contains interfaces for Project Model and messaging for scaffolding.
123
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
123
Microsoft.Build
This package contains the Microsoft.Build assembly which is used to create, edit, and evaluate MSBuild projects.
122
Microsoft.VisualStudio.Web.CodeGeneration.Contracts
Contains interfaces for Project Model and messaging for scaffolding.
121
Microsoft.Build.Utilities.Core
This package contains the Microsoft.Build.Utilities assembly which is used to implement custom MSBuild tasks.
121

.NET Framework 4.6.2

.NET 8.0

  • No dependencies.

.NET 9.0

  • No dependencies.

.NET Standard 2.0

Version Downloads Last updated
10.0.0 6 11/12/2025
10.0.0-rc.2.25502.107 19 10/15/2025
10.0.0-rc.1.25451.107 33 9/9/2025
10.0.0-preview.7.25380.108 25 8/12/2025
10.0.0-preview.6.25358.103 40 7/15/2025
10.0.0-preview.5.25277.114 30 6/7/2025
10.0.0-preview.4.25258.110 40 5/16/2025
10.0.0-preview.3.25171.5 39 4/13/2025
10.0.0-preview.2.25163.2 46 3/21/2025
10.0.0-preview.1.25080.5 68 2/26/2025
9.0.11 6 11/12/2025
9.0.10 13 10/15/2025
9.0.9 32 9/9/2025
9.0.8 38 8/5/2025
9.0.7 42 7/9/2025
9.0.6 47 6/12/2025
9.0.5 41 5/16/2025
9.0.4 57 4/13/2025
9.0.3 55 3/12/2025
9.0.2 65 2/17/2025
9.0.1 77 1/18/2025
9.0.0 77 11/14/2024
9.0.0-rc.2.24473.5 59 10/15/2024
9.0.0-rc.1.24431.7 68 9/12/2024
9.0.0-preview.7.24405.7 58 8/14/2024
9.0.0-preview.6.24327.7 69 7/10/2024
9.0.0-preview.5.24306.7 64 6/14/2024
9.0.0-preview.4.24266.19 55 6/4/2024
9.0.0-preview.3.24172.9 67 4/23/2024
9.0.0-preview.2.24128.5 63 3/16/2024
9.0.0-preview.1.24080.9 62 3/1/2024
8.0.0 95 11/15/2023
8.0.0-rc.2.23479.6 70 10/13/2023
8.0.0-rc.1.23419.4 75 9/22/2023
8.0.0-preview.7.23375.6 94 8/16/2023
8.0.0-preview.6.23329.7 65 7/30/2023
8.0.0-preview.5.23280.8 70 7/31/2023
8.0.0-preview.4.23259.5 85 8/1/2023
8.0.0-preview.3.23174.8 76 5/14/2023
8.0.0-preview.2.23128.3 81 3/29/2023
8.0.0-preview.1.23110.8 72 2/22/2023
7.0.0 76 12/4/2022
7.0.0-rc.2.22472.3 78 10/21/2022
7.0.0-rc.1.22426.10 75 9/15/2022
7.0.0-preview.7.22375.6 97 9/15/2022
7.0.0-preview.6.22324.4 68 9/15/2022
7.0.0-preview.5.22301.12 69 6/27/2022
7.0.0-preview.4.22229.4 77 6/28/2022
7.0.0-preview.3.22175.4 88 6/28/2022
7.0.0-preview.2.22152.2 65 6/28/2022
7.0.0-preview.1.22076.8 61 6/28/2022
6.0.2-mauipre.1.22102.15 82 6/28/2022
6.0.2-mauipre.1.22054.8 79 6/28/2022
6.0.1 62 11/13/2024
6.0.0 96 6/28/2022
6.0.0-rc.2.21480.5 68 6/28/2022
6.0.0-rc.1.21451.13 70 6/28/2022
6.0.0-preview.7.21377.19 79 6/28/2022
6.0.0-preview.6.21352.12 94 6/28/2022
6.0.0-preview.5.21301.5 85 6/28/2022
6.0.0-preview.4.21253.7 72 6/28/2022
6.0.0-preview.3.21201.4 90 6/28/2022
6.0.0-preview.2.21154.6 66 6/28/2022
6.0.0-preview.1.21102.12 69 6/28/2022
5.0.0 74 6/28/2022
5.0.0-rc.2.20475.5 69 6/28/2022
5.0.0-rc.1.20451.14 93 6/28/2022
5.0.0-preview.8.20407.11 77 6/28/2022
5.0.0-preview.7.20364.11 73 6/28/2022
5.0.0-preview.6.20305.6 65 6/28/2022
5.0.0-preview.5.20278.1 88 6/28/2022
5.0.0-preview.4.20251.6 73 6/28/2022
5.0.0-preview.3.20214.6 86 6/28/2022
5.0.0-preview.2.20160.6 68 6/28/2022
5.0.0-preview.1.20120.5 90 6/28/2022
1.7.1 85 6/28/2022
1.7.0 91 6/28/2022
1.7.0-preview3.19551.4 69 6/28/2022
1.7.0-preview2.19523.17 91 6/28/2022
1.7.0-preview1.19504.10 67 6/28/2022
1.6.0 84 6/28/2022
1.6.0-rc1.19456.4 84 6/28/2022
1.6.0-preview9.19421.4 85 6/28/2022
1.6.0-preview9.19416.11 68 6/28/2022
1.6.0-preview8.19405.3 85 6/28/2022
1.6.0-preview7.19362.9 71 6/28/2022
1.6.0-preview6.19303.8 90 6/28/2022
1.6.0-preview6.19264.9 80 6/28/2022
1.6.0-preview5.19224.8 87 6/28/2022
1.6.0-preview4.19212.13 92 6/28/2022
1.6.0-preview3.19128.7 76 6/28/2022
1.6.0-preview.19073.11 71 6/28/2022
1.6.0-preview.18571.3 90 6/28/2022
1.5.0 96 6/28/2022
1.5.0-rc1 69 6/28/2022
1.5.0-preview2-26406-04 72 6/28/2022
1.5.0-preview1-26216-02 66 6/28/2022
1.4.0 103 6/28/2022
1.4.0-preview2-25405-01 84 6/28/2022
1.4.0-preview1-25305-02 68 6/28/2022
1.3.1 104 6/28/2022
1.3.0 87 6/28/2022
1.3.0-preview1-24530-04 80 6/28/2022
1.2.0 84 6/28/2022
1.2.0-rc2-24027 64 6/28/2022
1.1.38-beta-23516 68 6/28/2022
1.1.38-beta-23409 90 6/28/2022
1.1.38-beta-23225 85 6/28/2022
1.1.37 88 6/28/2022
1.1.37-beta-23109 83 6/28/2022
1.1.37-beta-23019 88 6/28/2022
1.1.36 83 6/28/2022
1.1.34-rc 75 6/28/2022
1.1.33-beta 75 6/28/2022
1.1.32-beta 82 6/28/2022