6.元字符-分组.html 919 B

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  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4. <meta charset="UTF-8">
  5. <meta name="viewport" content="width=device-width, initial-scale=1.0">
  6. <title>Document</title>
  7. </head>
  8. <body>
  9. <script>
  10. const reg = /(ab)c/;
  11. console.log(reg.test("abcabdcba")); //false
  12. console.log(reg.test('ab')); // false
  13. // 2025-03-29
  14. const data = '2025-03-29';
  15. // 03/29/2025
  16. const reg1 = /^(\d{4})-(\d{2})-(\d{2})$/
  17. console.log(reg1.test(data));
  18. // $1 $2 $3
  19. // 分组捕获
  20. console.log(data.replace(reg1,'$2~$3~$1'))
  21. // 分支结构
  22. const a1 = 'www';
  23. const a2 = 'aaa';
  24. const a3 = 'vvv';
  25. const a4 = 'ggg';
  26. const reg2 = /www|ggg/;
  27. console.log(reg2.test(a1));
  28. console.log(reg2.test(a2));
  29. console.log(reg2.test(a3));
  30. console.log(reg2.test(a4));
  31. </script>
  32. </body>
  33. </html>