正規表達式測試器

// 驗證電子郵件格式
const emailRe = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
console.log(emailRe.test('user@example.com')); // true

// 擷取命名群組（日期解析）
const dateRe = /(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})/g;
const text = '會議時間：2026-03-12，截止：2026-04-01';
const matches = [...text.matchAll(dateRe)];
for (const m of matches) {
  console.log(m.groups.year, m.groups.month, m.groups.day);
}

// 取代：日期格式轉換 YYYY-MM-DD → MM/DD/YYYY
const reformatted = text.replace(dateRe, '$<month>/$<day>/$<year>');
console.log(reformatted);
// 會議時間：03/12/2026，截止：04/01/2026

import re

# 尋找所有匹配項
text = '聯絡：alice@example.com，bob@test.org'
emails = re.findall(r'[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}', text)
print(emails)  # ['alice@example.com', 'bob@test.org']

# 命名群組擷取（Python 用 ?P<name> 語法）
date_pattern = r'(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})'
m = re.search(date_pattern, '發布於 2026-03-12')
if m:
    print(m.group('year'), m.group('month'), m.group('day'))

# 取代：手機號碼中間4位遮罩
phone_re = r'(1[3-9]\d)\d{4}(\d{4})'
result = re.sub(phone_re, r'\1****\2', '手機號碼：13812345678')
print(result)  # 手機號碼：138****5678

import java.util.regex.*;

class RegexDemo {
    public static void main(String[] args) {
        String text = "Error [2026-03-12 18:05:09] Connection failed";

        // 編譯正規（生產環境應快取 Pattern 實例）
        Pattern p = Pattern.compile(
            "(?<level>INFO|WARN|ERROR)\\s+\\[(?<time>[^\\]]+)\\]\\s+(?<message>.+)"
        );
        Matcher m = p.matcher(text);

        if (m.find()) {
            System.out.println("級別: " + m.group("level"));
            System.out.println("時間: " + m.group("time"));
            System.out.println("訊息: " + m.group("message"));
        }

        // 取代所有數字
        String cleaned = "abc123def456".replaceAll("\\d+", "*");
        System.out.println(cleaned); // abc*def*
    }
}