Log Level Regex Pattern

Match standard log level keywords

•

Difficulty

Language

none

Flags

// Regular Expression

Live Regex Tester

Pattern

Flags

Test String

Pattern Breakdown

Character class [ ]

Group ( )

Quantifier { }

Anchor ^ $

Repetition * + ?

Escape \

Alternation |

Any char .

Code Examples

JavaScript

const regex = /\b(DEBUG|INFO|WARN|ERROR|FATAL|TRACE)\b/undefined;
const test = "undefined";
console.log(regex.test(test)); // true

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

Python

import re

pattern = r'\b(DEBUG|INFO|WARN|ERROR|FATAL|TRACE)\b'
test = "undefined"
match = re.search(pattern, test)
print(match)  # Found!

Go

package main

import (
    "fmt"
    "regexp"
)

func main() {
    re := regexp.MustCompile(`\b(DEBUG|INFO|WARN|ERROR|FATAL|TRACE)\b`)
    fmt.Println(re.MatchString("undefined")) // true
}

Common Use Cases

Match Examples

Input	Result
	Match
	No Match

About the Log Level Regex

Match standard log level keywords

Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The log level pattern. 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 Log Level regex pattern?

Match standard log level keywords

How do I use the Log Level regex?

What does this Log Level regex match?

Is the Log Level regex beginner-friendly?

This pattern is rated Intermediate. It uses advanced features like lookaheads, backreferences, or complex alternation.

What languages support the Log Level 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 Log Level 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.