Lookahead (Positive) Regex Pattern

Live Regex Tester

Pattern Breakdown

Code Examples

const regex = /\w+(?=\s+is)/g;
const test = "JavaScript is awesome";
console.log(regex.test(test)); // true

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

import re

pattern = r'\w+(?=\s+is)'
test = "JavaScript is awesome"
match = re.findall(pattern, test)
print(match)  # Found!

package main

import (
    "fmt"
    "regexp"
)

func main() {
    re := regexp.MustCompile(`\w+(?=\s+is)`)
    fmt.Println(re.MatchString("JavaScript is awesome")) // true
}

Common Use Cases

Match Examples

About the Lookahead (Positive) Regex

Demonstrates positive lookahead: matches a word only if followed by " is". Lookaheads check without consuming characters.

Regular expressions (regex) are powerful pattern matching tools used across virtually all programming languages. The lookahead (positive) pattern is classified as advanced difficulty in the advanced patterns 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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