System.Collections.Immutable

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

• Collections and Data Structures
• API 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.