C#idiomatic C#
ide0056fundamentals/code-analysis/style-rules

Code analysis

Use index operator (IDE0056)

Learn about code analysis rule IDE0056: Use index operator

IDE0056 Style / Language rules (expression-level preferences)
Applicable languages C# 8.0+Options csharp_style_prefer_index_operator

Overview

This style rule concerns the use of the index-from-end operator (^), which is available in C# 8.0 and later.

Options

Options specify the behavior that you want the rule to enforce. For information about configuring options, see Option format.

csharp_style_prefer_index_operator

Property Value Description
Option name csharp_style_prefer_index_operator
Option values true Prefer to use the ^ operator when calculating an index from the end of a collection
false Prefer not to use the ^ operator when calculating an index from the end of a collection
Default option value true
csharp
// csharp_style_prefer_index_operator = true
string[] names = { "Archimedes", "Pythagoras", "Euclid" };
var index = names[^1];

// csharp_style_prefer_index_operator = false
string[] names = { "Archimedes", "Pythagoras", "Euclid" };
var index = names[names.Length - 1];

Suppress a warning

If you want to suppress only a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

csharp
#pragma warning disable IDE0056
// The code that's violating the rule is on this line.
#pragma warning restore IDE0056

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

ini
[*.{cs,vb}]
dotnet_diagnostic.IDE0056.severity = none

To disable all of the code-style rules, set the severity for the category Style to none in the configuration file.

ini
[*.{cs,vb}]
dotnet_analyzer_diagnostic.category-Style.severity = none

For more information, see How to suppress code analysis warnings.

See also