Regular Expression (2), expression (2)

Regular Expression (2), expression (2)

Continue with the previous article.

 

/* Use grouping mode to match */var pattern =/8 (. *) 8 //; // get 8 .. any character between 8 var str = 'goo8gle8'; str. match (pattern); alert (RegExp. $1); // gle to obtain the string content var pattern =/8 (. *) 8 //; // get 8 .. any character between 8 var str = 'goo8gle8'; var result = str. replace (pattern, '<strong> $1 </strong>'); // obtain the replaced string and output document. write (result );

Running result:

 

 

Var pattern = /(. *) \ s (. *)/; var str = 'Google baidu'; var result = str. replace (pattern, '$2 $ 1'); // replace the values of the two groups with the output document. write (result );

Running result:

 

 

Greedy and inert

 

 

/* About greed and inertia */var pattern =/[a-z] +? /;//? If greedy match is disabled, only one var str = 'abcdefance' is replaced; var result = str. replace (pattern, 'xxx'); alert (result );

Running result:

 

 

Varpattern =/8 (. + ?) 8 // No greedy, enabled global (another type of No greedy/8 ([^ 8] *) 8/) var str = 'a8b8c8d8e8f112 '; var result = str. replace (pattern, '<strong> $1 </strong>'); document. write (result );

Running result:

 

 

/* Use exec to return the array */var pattern =/^ [a-z] + \ s [0-9] {4} $/I; // match var str = 'Google 55'{alert(pattern.exe c (str) between the beginning and end of the line; // return the entire string var pattern =/^ [a-z] +/I; // match only the letter var str = 'Google 55'{alert(pattern.exe c (str); // return google var pattern =/^ ([a-z] +) \ s ([0-9] {4}) $/I; // use the grouping var str = 'Google 2015'{alert(pattern.exe c (str) [0]); // return google5alert(pattern.exe c (str) [1]); // return googlealert(pattern.exe c (str) [2]); // return 2015/* capturing group and non-capturing Group */var pattern =/(\ d +) ([a-z] + )/; // capture group var str = '55google'{alert(pattern.exe c (str ));

Running result:

 

 

Var pattern =/(\ d + )(? : [A-z]) // non-capturing group var str = '55google'{alert(pattern.exe c (str ));

Running result:

 

 

/* Use grouping nesting */var pattern =/(? (B? (C ?))) // Obtain var str = 'abc'externalert(pattern.exe c (str) from the external directory ));

Running result:

 

 

/* Use forward-looking capture */var pattern =/(goo (? = Gle) //; // goo must be followed by gle to capture var str = 'google'externalert(pattern.exe c (str); // goo, goo/* match with special characters */var pattern = /\. \ [\/B \]/; // special character. Use the \ symbol to escape var str = '. [/bw.'{alert(pattern.exe c (str ));//. [/B]/* use line feed mode */var pattern =/^ \ d +/mg; // enable line feed mode var str = '1. baidu \ n2.google \ n3.bing '; var result = str. replace (pattern, '#'); // 1/2/3 replace alert (result) );

Running result:

 

 

Common Regular Expressions

 

/* Check the zip code */var pattern =/[1-9] [0-9] {5}/; // six digits in total, the first digit cannot be 0var str = '20140901'; alert (pattern. test (str); // true/* Check the compressed file package */var pattern =/[\ w] + \. zip | rar | gz/; // \ w all numbers and letters and _ var str = '123.gz '; alert (pattern. test (str); // true/* remove unnecessary Spaces */var pattern =/\ s/g; var str = '1 2 3'; var result = str. replace (pattern, ''); alert (result); // 123/* Delete spaces at the beginning and end */var pattern =/^ \ s +/g; // force the first var str = '1 2 3'; var result = str. replace (pattern, ''); pattern =/\ s + $/; // force end result = result. replace (pattern, ''); alert ('|' + result + '|'); // 123

Running result (force beginning/end ):

 

 

 

/* Simple email verification */var pattern =/^ ([a-zA-Z0-9 _ \.] +) @ ([a-zA-Z0-9 _ \.] + )\. ([a-zA-Z] {2, 4})/; var str = 'yc60. com@gmail.com '; alert (pattern. test (str); // true