A regular expression-php Tutorial

A regular expression problem

$string='dj%a3%a3999';if(preg_match('/^[dj]{2}([(\%23)(\%a3\%a3)])((\w)+)$/i', $string,$result)){ print_r($result);}

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Reply to discussion (solution)

You 'd better talk about your requirements. The middle section shows that your regular expressions are messy.

/* The requirement is that one dj group % a3 % a3 or % 23 is another group. 999 is a group that obtains the corresponding data through $ result. For example: */$ result [0] = 'DJ'; $ result [1] = '% a3 % a3'; $ result [2] = '2016 ';

$s = 'dj%a3%a3999';preg_match('/([^%]+)((?:%a3|23)+)(.+)/', $s, $r);print_r($r);

Array ([0] => dj % a3 % a3999 [1] => dj [2] => % a3 % a3 [3] => 999)

This is used:

$string='dj%a3%a3999';if(preg_match('/^([dj]{2})([%a3]+)(\d{3})$/i', $string,$result)){ print_r($result);}

Result:

Array ( [0] => dj%a3%a3999 [1] => dj [2] => %a3%a3 [3] => 999 )

$s = 'dj%a3%a3999';preg_match('/([^%]+)((?:%a3|23)+)(.+)/', $s, $r);print_r($r);

Array ([0] => dj % a3 % a3999 [1] => dj [2] => % a3 % a3 [3] => 999)

If $ s = 'DJ % 100'; then no.

This is used:

$string='dj%a3%a3999';if(preg_match('/^([dj]{2})([%a3]+)(\d{3})$/i', $string,$result)){ print_r($result);}

[/Code]
This string also needs to match: $ string = 'DJ % 100 ';

$ S = 'DJ % 8080 ';
Preg_match ('/([^ %] + )((? : % (? : A3 | 23) +) (. +)/', $ s, $ r );
Or
Preg_match ('/([^ %] + )((? : % A3 | % 23) +) (. +)/', $ s, $ r );

Regular expression rules are described as follows:
| If ambiguity occurs during calculation, you must list them one by one or enclose them in parentheses.

Apparently (? % A3 | 23). % is combined with a3, causing ambiguity.

Boss, can you help me explain that I see many regular expressions added in front of them? : I want to know what this means?

(? :...) Is the same as (...) grouping, but the result does not show a result set.

(? :...) Is the same as (...) grouping, but the result does not show a result set.

Boss, can you match an address for me? for example:

Www.sohu.com, www.baidu.com, www.yahoo.com. n

In this way, a maximum of nine URLs can be connected, including sohu.com, baidu.com, and yahoo.com.cn.

(?! (W) (\ w + (-\ w +) *) (\. (\ w + (-\ w + )*))*