https://github.com/bgrainger/IndexRange

Implementations of System.Index and System.Range for netstandard2.0 and .NET Framework.
https://github.com/bgrainger/IndexRange

Last synced: 7 days ago
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Implementations of System.Index and System.Range for netstandard2.0 and .NET Framework.

• Host: GitHub
• URL: https://github.com/bgrainger/IndexRange
• Owner: bgrainger
• License: mit
• Created: 2019-10-02T22:06:55.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2023-08-22T14:13:08.000Z (about 1 year ago)
• Last Synced: 2024-10-27T11:13:37.856Z (17 days ago)
• Language: C#
• Homepage: https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#indices-and-ranges
• Size: 64.5 KB
• Stars: 80
• Watchers: 5
• Forks: 4
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# IndexRange

This repository provides implementations (copied [from corefx](https://github.com/dotnet/corefx/tree/d152d19f0be3dcea1a32f452e9d9940e990574d7/src/Common/src/CoreLib/System))

of `System.Index` and `System.Range` for `netstandard2.0` and .NET Framework.

This lets you use the new C# 8.0 [index and range features](https://docs.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-8#indices-and-ranges) in projects that target

.NET Framework or `netstandard2.0`.

## Installing

[![NuGet Pre Release](https://img.shields.io/nuget/v/IndexRange.svg)](https://www.nuget.org/packages/IndexRange/)

The package is available [on NuGet](https://www.nuget.org/packages/IndexRange). To install, run:

```

dotnet add package IndexRange

```

## Build Status

[![Build Status](https://dev.azure.com/bgrainger/Public/_apis/build/status/bgrainger.IndexRange?branchName=master)](https://dev.azure.com/bgrainger/Public/_build/latest?definitionId=3&branchName=master)

## Using Range with Arrays

The C# compiler needs the `RuntimeHelpers.GetSubArray` method to be available to create subranges from arrays. This method is only available in `netstandard2.1`

and .NET Core 3.0, so creating subranges from arrays will fail to compile in .NET Framework.

### Use Span\

A workaround is to add a reference to [System.Memory](https://www.nuget.org/packages/System.Memory/) and use `Span`. Not only does this compile, it's much more

efficient as it doesn't create a new array and copy the sliced data to it:

```csharp

int[] array = new[] { 1, 2, 3, 4, 5, 6 };

// don't do this:

// var slice = array[1..^1];

// do this:

var slice = array.AsSpan()[1..^1];

```

### Define GetSubArray\

The other fix is to define the necessary method in your source code. Copy the following code into your project:

https://gist.github.com/bgrainger/fb2c18659c2cdfce494c82a8c4803360

That type is not in this NuGet package so that the C# compiler doesn't warn that `The predefined type 'RuntimeHelpers' is defined in multiple assemblies`.