BytePane

Hashtag Regex Pattern

Extracts hashtags starting with # followed by a letter and optional alphanumeric/underscore characters.

T
Text & Strings
Beginner
Difficulty
Universal
Language
g
Flags
// Regular Expression
/#[a-zA-Z][a-zA-Z0-9_]*/g

Live Regex Tester

Pattern Breakdown

#[a-zA-Z][a-zA-Z0-9_]*
Character class [ ]
Group ( )
Quantifier { }
Anchor ^ $
Repetition * + ?
Escape \
Alternation |
Any char .

Code Examples

JavaScript

const regex = /#[a-zA-Z][a-zA-Z0-9_]*/g;
const test = "#JavaScript #coding";
console.log(regex.test(test)); // true

// Extract matches
const matches = test.match(regex);
console.log(matches);

Python

import re

pattern = r'#[a-zA-Z][a-zA-Z0-9_]*'
test = "#JavaScript #coding"
match = re.findall(pattern, test)
print(match)  # Found!

Go

package main

import (
    "fmt"
    "regexp"
)

func main() {
    re := regexp.MustCompile(`#[a-zA-Z][a-zA-Z0-9_]*`)
    fmt.Println(re.MatchString("#JavaScript #coding")) // true
}

Common Use Cases

Social media parsingcontent taggingtrend analysis

Match Examples

InputResult
#JavaScript #codingMatch
#123No Match

About the Hashtag Regex

Extracts hashtags starting with # followed by a letter and optional alphanumeric/underscore characters.

Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The hashtag pattern is classified as beginner difficulty in the text & strings category. It works in all major programming languages.

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.

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Frequently Asked Questions

What is the Hashtag regex pattern?

Extracts hashtags starting with # followed by a letter and optional alphanumeric/underscore characters.

How do I use the Hashtag regex?

Use the pattern /#[a-zA-Z][a-zA-Z0-9_]*/g in your code. In JavaScript: new RegExp('#[a-zA-Z][a-zA-Z0-9_]*', 'g'). Test it above with your own input.

What does this Hashtag regex match?

This pattern matches: "#JavaScript #coding". It does NOT match: "#123". Social media parsing, content tagging, trend analysis.

Is the Hashtag regex beginner-friendly?

This pattern is rated Beginner. It uses basic regex syntax and is easy to understand.

What languages support the Hashtag regex?

This pattern works in all major programming languages including JavaScript, Python, Java, C#, Go, Ruby, PHP, and more. Syntax may vary slightly between regex engines.

Can I modify the Hashtag 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.

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