Atomic Group Simulation Regex Pattern
Simulates atomic groups in JavaScript using lookahead with backreference. Prevents catastrophic backtracking.
Live Regex Tester
Pattern Breakdown
Code Examples
JavaScript
const regex = /(?=(\d+))\1\s/g; const test = "123 "; console.log(regex.test(test)); // true // Extract matches const matches = test.match(regex); console.log(matches);
Python
import re pattern = r'(?=(\d+))\1\s' test = "123 " match = re.findall(pattern, test) print(match) # Found!
Go
package main
import (
"fmt"
"regexp"
)
func main() {
re := regexp.MustCompile(`(?=(\d+))\1\s`)
fmt.Println(re.MatchString("123 ")) // true
}Common Use Cases
Match Examples
| Input | Result |
|---|---|
| 123 | Match |
| abc | No Match |
About the Atomic Group Simulation Regex
Simulates atomic groups in JavaScript using lookahead with backreference. Prevents catastrophic backtracking.
Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The atomic group simulation pattern is classified as advanced difficulty in the advanced patterns category. This pattern is specifically designed for JavaScript.
When using this regex, always consider edge cases and test thoroughly with real-world data. Use the interactive tester above to validate the pattern against your specific inputs before deploying to production.
More Advanced Patterns Patterns
Need More Regex Patterns?
Browse our complete library of 100+ regex patterns with interactive testers.
Frequently Asked Questions
What is the Atomic Group Simulation regex pattern?
Simulates atomic groups in JavaScript using lookahead with backreference. Prevents catastrophic backtracking.
How do I use the Atomic Group Simulation regex?
Use the pattern /(?=(\d+))\1\s/g in your code. In JavaScript: new RegExp('(?=(\d+))\1\s', 'g'). Test it above with your own input.
What does this Atomic Group Simulation regex match?
This pattern matches: "123 ". It does NOT match: "abc ". Performance optimization, backtracking prevention.
Is the Atomic Group Simulation regex beginner-friendly?
This pattern is rated Advanced. It uses advanced features like lookaheads, backreferences, or complex alternation.
What languages support the Atomic Group Simulation regex?
This pattern works in JavaScript. Syntax may vary slightly between regex engines.
Can I modify the Atomic Group Simulation regex for my use case?
Yes! Use the interactive tester above to modify the pattern and test with your own data. Common modifications include making it case-insensitive (add 'i' flag), matching globally (add 'g' flag), or adjusting character classes.
Related Tools
Balanced Parentheses Regex
Intermediate Advanced Patterns pattern
Lookahead (Positive) Regex
Advanced Advanced Patterns pattern
Lookbehind (Positive) Regex
Advanced Advanced Patterns pattern
Named Capture Groups Regex
Advanced Advanced Patterns pattern
Non-Greedy Matching Regex
Intermediate Advanced Patterns pattern
Conditional with Alternation Regex
Intermediate Advanced Patterns pattern