WebToolPanel

Regex Tester & Generator

Test regular expressions against sample text, highlight matches, and generate example strings.

g:Global: Finds all matches rather than stopping after the first.
i:Ignore case: Case-insensitive matching.
m:Multiline: ^ and $ match start/end of lines, not just string ends.
s:DotAll: The . meta-character matches newline characters.
u:Unicode: Treat pattern as a sequence of Unicode code points.
y:Sticky: Matches only from lastIndex position in the target string.

Matches

No matches found.

Frequently Asked Questions

What is a regular expression (regex)?

A regular expression is a sequence of characters that defines a search pattern. It's used to find, match, and manage text based on specific rules.

Why are regular expressions useful?

Regex are powerful for input validation (like emails or passwords), searching and replacing text, data extraction from large text bodies, and parsing complex strings.

What are common regex metacharacters?

Common metacharacters include `.` (any character), `*` (zero or more occurrences), `+` (one or more), `?` (zero or one), `[]` (character set), `()` (capturing group), and `\` (escape character).

What are regex flags?

Regex flags modify the search behavior. Common flags are 'g' (global search, find all matches), 'i' (ignore case), and 'm' (multiline, ^ and $ match start/end of lines).

How can I learn regular expressions effectively?

Start with basic syntax, practice with online testers using sample strings, understand metacharacters and quantifiers, and gradually build more complex patterns. Many online tutorials and cheat sheets can help.

Can regex be used in different programming languages?

Yes, most modern programming languages like Python, JavaScript, Java, PHP, Ruby, C#, and Perl have built-in support or libraries for using regular expressions.

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