How to Use the Regex Generator

Regular expressions (regex) are powerful tools for searching, matching, and manipulating text based on patterns. This tool allows you to:

1. Select or Customize Patterns

Choose a predefined pattern (digits, letters, alphanumeric, etc.) or provide your own custom regex pattern.

2. Specify Repetitions

You can choose how many times the pattern should repeat using options like zero or more times (*), one or more times (+), optional (?), or exactly N times.

3. View Matches

Enter example text, and the regex generator will search the text for the pattern. Any matches will be highlighted in the text for easy identification.

Interactive Regex Tutorial

Regular expressions (regex) are powerful tools for searching, matching, and manipulating text based on patterns. Below are some basic and advanced regex syntax and examples that you can test using the regex generator.

Basic Regex Syntax

• \d - Matches any digit (0-9)
• [A-Za-z] - Matches any letter (uppercase or lowercase)
• \s - Matches any whitespace character (spaces, tabs)
• ^ - Matches the start of a string
• $ - Matches the end of a string

Advanced Regex Patterns

• (abc) - Capturing group for 'abc'
• | - OR operator (e.g., a|b matches 'a' or 'b')
• [A-Za-z0-9] - Matches any alphanumeric character
• \b - Word boundary (matches positions where a word starts or ends)
• (?:abc) - Non-capturing group (groups the expression but doesn’t capture the match)

Quantifiers

• * - Matches 0 or more occurrences
• + - Matches 1 or more occurrences
• ? - Matches 0 or 1 occurrence (optional)
• {n} - Matches exactly n occurrences
• {n,} - Matches n or more occurrences
• {n,m} - Matches between n and m occurrences

Lookaheads and Lookbehinds

• (?=abc) - Positive lookahead (asserts that 'abc' follows)
• (?!abc) - Negative lookahead (asserts that 'abc' does not follow)
• (?<=abc) - Positive lookbehind (asserts that 'abc' precedes)
• (? - Negative lookbehind (asserts that 'abc' does not precede)

Common Regex Use Cases

• Validating Email: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}
• Finding URLs: https?:\/\/[^\s]+
• Extracting Numbers: \d+
• Finding Hex Colors: #[A-Fa-f0-9]{6}

Test these patterns in the regex generator to see how they work in your example text!