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Use range operator (IDE0057)

  • Article
Property Value
Rule ID IDE0057
Title Use range operator
Category Style
Subcategory Language rules (expression-level preferences)
Applicable languages C# 8.0+
Options csharp_style_prefer_range_operator

Overview

This style rule concerns the use of the range 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_range_operator

Property Value Description
Option name csharp_style_prefer_range_operator
Option values true Prefer to use the range operator .. when extracting a "slice" of a collection
false Prefer not to use the range operator .. when extracting a "slice" of a collection
Default option value true 
// csharp_style_prefer_range_operator = true
string sentence = "the quick brown fox";
var sub = sentence[0..^4];

// csharp_style_prefer_range_operator = false
string sentence = "the quick brown fox";
var sub = sentence.Substring(0, sentence.Length - 4);

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.

#pragma warning disable IDE0057
// The code that's violating the rule is on this line.
#pragma warning restore IDE0057

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

[*.{cs,vb}]
dotnet_diagnostic.IDE0057.severity = none

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

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

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

See also