PHP Regexp (PCRE) - Find a set of all substrings

问题

I have the following string, for example:

aaXXccYYeeXX_ZZkkYYmmXX_ZZnnXXooYYuuXX_ZZvv

How can I find all XX.*YY.*ZZ parts in the string? (possibly by using preg_match())

XX cc YY eeXX_ ZZ
XX _ZZkk YY mmXX_ ZZ
XX _ZZnnXXoo YY uuXX_ ZZ
XX oo YY uuXX_ ZZ

Plus all longer matches, as:

XX cc YY eeXX_ZZkkYYmmXX_ZZnnXXooYYuuXX_ ZZ

回答1:

Thank everybody for help.

My solution based on 'bobbogo' solution. Thank you.

Regular expression:

(?=(XX.*?YY.*?ZZ))(?=(.*ZZ))

Result (from RegexBuggy):

1 XXccYYeeXX_ZZ     XXccYYeeXX_ZZkkYYmmXX_ZZnnXXooYYuuXX_ZZ
2 XX_ZZkkYYmmXX_ZZ      XX_ZZkkYYmmXX_ZZnnXXooYYuuXX_ZZ
3 XX_ZZnnXXooYYuuXX_ZZ  XX_ZZnnXXooYYuuXX_ZZ
4 XXooYYuuXX_ZZ     XXooYYuuXX_ZZ

Possible it can by more optimized? I am not big professional in regex.

回答2:

This seems quite straight forward at first glance (apologies if I am missing something). For the first part, use repeated matches of:

XX(.*?)YY(.*?)ZZ

For the longer match I suggest a separate match of:

XX(.*?)YY(.*)ZZ

EDIT

Aha! the patterns overlap (thanks folks). In this case, you will have to loop. Probably easiest to strip off any leading .*?XX before re-trying the match. In perl land you would use

while (/XX(.*?)YY(.*?)ZZ/) {
    print "[$1] [$2]\n";
    s/^.*?XX//;
}

If you are desperate for a single regex, then m//g in array context will come to your rescue. (Not sure what the corresponding php might look like.)

@a = /XX(?=(.*?YY.*?ZZ))/g;

The array @a will contain the overlapping strings, but with the initial XX stripped off.

来源：https://stackoverflow.com/questions/5231482/php-regexp-pcre-find-a-set-of-all-substrings

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