Pattern

Regex for Regex flag string

Flag characters used in JS regex literals.

The Regex flag string regex is ^[gimsuyd]*$ — copy it below, or open it in the explainer for a token-by-token breakdown.

The pattern

^[gimsuyd]*$

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What it matches

g
gi
gimsu
gimsuy

What it doesn't match

gA
g g
x

Notes & gotchas

JavaScript regex flags: g (global), i (case-insensitive), m (multiline), s (dotall), u (unicode), y (sticky), d (hasIndices). Each flag at most once.

Code in your language

Use the explainer's Code tab to generate ready-to-paste snippets in JavaScript, Python, Java, .NET, Go, Ruby, and PHP for this pattern.

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Token-by-token breakdown

Every part of the pattern, left to right:

Token	Meaning
`^`	start of string (or line in multiline mode)
`[gimsuyd]*`	zero or more: any of: “g”, “i”, “m”, “s”, “u”, “y”, “d”
`$`	end of string (or line in multiline mode)

About this pattern

Developer-oriented patterns help with code analysis, log parsing, and data transformation. Use these in build scripts, CI tools, IDE search-and-replace, and code review utilities.

Quick usage in different languages

This exact pattern — with the correct escaping and idioms for each language:

JavaScript: /^[gimsuyd]*$/.test(value)
Python: re.match(r"^[gimsuyd]*$", value)
Java: Pattern.compile("^[gimsuyd]*$").matcher(value).matches()
C# / .NET: Regex.IsMatch(value, @"^[gimsuyd]*$")
Go: regexp.MustCompile(`^[gimsuyd]*$`).MatchString(value)
Ruby: /^[gimsuyd]*$/.match?(value)
PHP: preg_match('~^[gimsuyd]*$~', $value)

The explainer’s Code tab regenerates these for any pattern you paste, and the downloadable cheat sheet bundles the breakdown, all seven snippets, and the pitfalls below onto one printable page.

Common pitfalls

Anchored to the whole string. This pattern uses ^ and $, so it requires the entire input to match. To find it inside a longer text, drop the anchors and use the global (g) flag.
Validate beyond format. Matching the format doesn't guarantee the value is real. Confirm the regex flag string against a source of truth (database, API, or checksum) where it matters.

Standards & sources

This pattern is based on the following authoritative specification(s) and issuing authorities. Formats can change — always confirm against the primary source.

ECMAScript Language Specification (regex)

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