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JS regular advanced code to understand

2022-07-18 13:10:00 【Light of D】 

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    <p>1</p><p>2</p>
    <script> // Laziness matches  let text = '<p>1</p><p>2</p>'; let pattern0 = /<p>.*<\/p>/; let pattern = /<p>.*?<\/p>/; console.log(' Greedy matching ',pattern0.exec(text)); console.log(' Laziness matches ',pattern.exec(text)); // grouping () text = "mom and dad and baby"; pattern = /mom( and dad( and baby))/; console.log(' grouping ',pattern.exec(text)); // Non capture grouping (?:) pattern = /mom(?: and dad)( and baby)/; console.log(' Non capture grouping ',pattern.exec(text)); // Backtracking reference of group  text = '<p>1</p><p>2</p>'; pattern0 = /<(p)>.*<(\/\1)>.*<\1>.*<\2>/; console.log(' Backtracking reference of group ',pattern0.exec(text)); // Named capture groups  (?<name> Content ) ES9 New characteristics  // How to access the  exec The returned result is named groups Properties of , This object has the attribute we named  text = "mom and dad and baby"; pattern = /mom(?<dad_baby> and dad(?<baby> and baby))/; let result = pattern.exec(text); console.log(' Named capture groups ',pattern.exec(text)); console.log(result.groups.dad_baby); console.log(result.groups.baby); // Forward assertion  (?= expression )  To look right in a position , Indicates that the right side of the location must match the expression  text =' I like you   I like   I like me   like   Like you, '; pattern = / like (?= you )/g; var a; console.log(' Forward assertion ', a=pattern.exec(text),'index',a?.index); console.log(' Forward assertion ',a=pattern.exec(text),'index',a?.index); console.log(' Forward assertion ',a=pattern.exec(text),'index',a?.index); // Reverse look ahead assertion (?! expression ) pattern = / like (?! you )/g; console.log(' Reverse look ahead assertion ', a=pattern.exec(text),'index',a?.index); console.log(' Reverse look ahead assertion ',a=pattern.exec(text),'index',a?.index); console.log(' Reverse look ahead assertion ',a=pattern.exec(text),'index',a?.index); console.log(' Reverse look ahead assertion ',a=pattern.exec(text),'index',a?.index); // Forward and backward assertions ：(?<= expression ), To look left in a position , Indicates that the left side of the location must match the expression  pattern = /(?<= I ) like (?= you )/g; console.log(' Forward and backward assertions ', a=pattern.exec(text),'index',a?.index); console.log(' Forward and backward assertions ',a=pattern.exec(text),'index',a?.index); // Reverse backward assertion ：(?<! expression ), To look left in a position , Indicates that the left side of the location cannot match the expression  pattern = /(?<! I ) like (?! you )/g; console.log(' Reverse backward assertion ', a=pattern.exec(text),'index',a?.index); console.log(' Reverse backward assertion ',a=pattern.exec(text),'index',a?.index); // Regular extension ：dotAll  Pattern  ,s Represents this pattern  //dot .  Metacharacters   Any single character other than the newline character  let str = ` <ul> <li> <a> Shawshank's salvation </a> <p> Release date : 1994-09-10</p> </li> <li> <a> Forrest gump </a> <p> Release date : 1994-07-06</p> </li> </ul>`; // Declare regular  // const reg = /<li>\s+<a>(.*?)<\/a>\s+<p>(.*?)<\/p>/; const reg = /<li>.*?<a>(.*?)<\/a>.*?<p>(.*?)<\/p>/gs; // Perform matching  // const result = reg.exec(str); let result0; let data = []; while (result0 = reg.exec(str)) {
       data.push({
       title: result0[1], time: result0[2] }); } // Output results  console.log(data); // Assert advanced applications   // Assertions can be used to determine whether a string conforms to specific rules , For example, extract at least 8 A string  pattern = /(?=.*?[a-z])(?=.*?[A-Z]).{8,}/gm; pattern0 = /.{8,}(?<=[a-z].*?)(?<=[A-Z].*?)/gm; text =` Admin123456 pZUJLUpTL2 Tnut2eWPN1 wJxpVhVYi3 UySRo49ps Ig7AHzZ0J oYHMDdHCK9 yiyWKQnWo2 gTZEEkVrj1 8Ij12340as wdfqe#wefDdf444 Codejiaonang123 [email protected] 111111abc11ABc CodeJiaonang123 qwe 8848 123456 asd123 Adm123 Asd123 wjleif932 admin123 123admin 123asd123 ADMIN123()  Number 89757 888888888info masterxiao123 888888888A ` for (let i =0 ;i<16;i++){
       a=pattern.exec(text); console.log(' Standardize password mode 1 ', a?a[0]:' period '); } for (let i =0 ;i<16;i++){
       a=pattern0.exec(text); console.log(' Standardize password mode 2 ', a?a[0]:' period '); } </script>
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