PHP regular expression function preg _ PHP Tutorial

The regular expression function preg _ in PHP _. Preg_match (); used for regular expression matching, and only match once preg_match_all (); used for regular expression matching, all compliant with the rule will be matched preg_replace (); positive preg_match (); // used for regular expression matching, and only matches once

Preg_match_all (); // used for regular expression matching. all matching rules are matched.

Preg_replace (); // regular expression replacement function

Preg_splite (); // regular expression division function

Preg_match (mode, string subject, arraymatches)

Here, mode is a regular rule, string subject is the string to be matched, and arraymatches is the matching result array.

Example:

[Php]

$ Mode = '/[89]/'; // Match 8 or 9

$ Str = "djfkdsjk10903990sjdfdk ";

Preg_match ($ mode, $ str, $ arr );

Print_r ($ arr );

?>

Output:

[Html]

Array ([0] => 9)

Preg_match_all (mode, string subject, arraymatches)

This function is similar to the preg_match_all () function, but it matches all the required content and stores it in a string.

Example:

[Php]

$ Mode = '/[89]/'; // Match 8 or 9

$ Str = "dj33f44k88dsjk10903990sjdfdk ";

Preg_match_all ($ mode, $ str, $ arr );

Print_r ($ arr );

?>

Output:

[Html]

Array ([0] => Array ([0] => 8 [1] => 8 [2] => 9 [3] => 9 [4] => 9))

Preg_replace (mixed pattern, mixed replacement, mixed subject [, int limit])

Use regular expressions to replace related content, similar to the previously learned str_replace string replacement, but the function is better than it.

Features: 1. the replacement content can be a regular or array regular

2. the replacement content can be replaced by the modifier e.

Purpose: replace some complicated content and use it for content conversion.

Example 1 -- array regular:

[Php]

$ Mode = array ('/{title}/', '/{author}/', '/{url }/');

$ Re = array ("code cloud", "qianshou", "http://codecloud.duapp.com /");

$ Str = "title: {title}
Author: {author}
Url: {url }";

Echo"

";

If ($ tag = preg_replace ($ mode, $ re, $ str )){

Echo $ tag;

} Else {

Echo "cannot be replaced! ";

}

?>

Output:

[Html]

Title: code cloud

Author: qianshou

Address: http://codecloud.duapp.com/

Example 2 -- replace the ubb code:

[Php]

$ Str = "Welcome to my blog: [url] http://blog.csdn.net/qsyzb#/url]";

$ Re = preg_replace ('/\ [url \] (. *) \ [\/url \]/', "\ 1", $ str );

Echo "". $ re ."";

?>

Output:

[Html

Welcome to my blog: http://blog.csdn.net/qsyzb </a>

Preg_split (string pattern, string subject [, intlimit [, int flags])

Regular expressions are used to cut related content. similar to the previously learned explode cut function, explode only has limitations in one way.

Example:

[Php]

$ Mode = '/[,. #]/';

$ Str = 'one, two. three # four ';

If ($ tag = preg_split ($ mode, $ str )){

Print_r ($ tag );

} Else {

Echo "cannot be replaced! ";

}

?>

Output:

[Html]

Array

(

[0] => one

[1] => two

[2] => three

[3] => four

)

Http://www.bkjia.com/PHPjc/477144.htmlwww.bkjia.comtruehttp://www.bkjia.com/PHPjc/477144.htmlTechArticlepreg_match (); // used for regular expression matching, and only match once preg_match_all (); // used for regular expression matching, all compliant rules will be matched with preg_replace (); // positive...