Pattern Breakdown
Understanding the regex pattern ^[a-z0-9]+(?:-[a-z0-9]+)*$:
- ^ - Start of string
- $ - End of string
- ? - Optional (zero or one)
- + - One or more
- * - Zero or more
- [...] - Character class
- (...) - Capturing group
- (?:...) - Non-capturing group
Examples
| Input | Result | Explanation |
|---|---|---|
my-blog-post |
✓ Match | Valid slug |
post-123 |
✓ Match | Slug with numbers |
-invalid-slug |
✗ No Match | Starts with hyphen |
Has Spaces |
✗ No Match | Contains spaces |
Code Examples
JavaScript
JavaScript
const pattern = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
const text = "my-blog-post";
// Test if string matches
if (pattern.test(text)) {
console.log("Valid!");
}
// Extract matches
const matches = text.match(pattern);
console.log(matches);
Python
Python
import re
pattern = r'^[a-z0-9]+(?:-[a-z0-9]+)*$'
text = "my-blog-post"
# Test if string matches
if re.match(pattern, text):
print("Valid!")
# Find all matches
matches = re.findall(pattern, text)
print(matches)
PHP
PHP
<?php
$pattern = '/^[a-z0-9]+(?:-[a-z0-9]+)*$/';
$text = "my-blog-post";
// Test if string matches
if (preg_match($pattern, $text)) {
echo "Valid!";
}
// Find all matches
preg_match_all($pattern, $text, $matches);
print_r($matches);
?>
Java
Java
import java.util.regex.*;
String pattern = "^[a-z0-9]+(?:-[a-z0-9]+)*$";
String text = "my-blog-post";
Pattern p = Pattern.compile(pattern);
Matcher m = p.matcher(text);
if (m.matches()) {
System.out.println("Valid!");
}
Use Cases
Common applications: CMS systems, blog platforms, SEO-friendly URLs
- Form validation and input sanitization
- Data extraction and parsing
- Search and replace operations
- API request/response validation
- Log file analysis
Frequently Asked Questions
What is the regex pattern for url slug regex?
The regex pattern is: ^[a-z0-9]+(?:-[a-z0-9]+)*$. Validate URL-friendly slugs. Allows lowercase letters, numbers, and hyphens (not at start/end).
How do I use the url slug regex pattern in JavaScript?
In JavaScript: const regex = new RegExp('^[a-z0-9]+(?:-[a-z0-9]+)*$'); or const regex = /^[a-z0-9]+(?:-[a-z0-9]+)*$/;
Does this pattern work in Python?
Yes, use: import re; pattern = re.compile(r'^[a-z0-9]+(?:-[a-z0-9]+)*$') in Python. Most regex patterns are cross-language compatible.
What are common use cases for url slug regex?
CMS systems, blog platforms, SEO-friendly URLs
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