没有连续空间RegEx Group PHP

Question

^([A-Za-z0-9 ]){8,12}

How do I turn this into something that can have spaces any where but not consecutively?

Id est:

A L L 0 W E D

N O T  A L L 0 W E D # Note two spaces between `not` and `allowed`

Answer 1

You can use lookahead/behind technique, like the following: '/^([A-Za-z0-9]| (?! )){8,12}/' . It means we expect AZ, az and 0-9 OR space, but not followed by space. Take a look at the result:

$strs = array(
    '12345678',
    'A L L 0 W E D',
    'N O T  A L L 0 W E D' # Note two spaces between `not` and `allowed`
);

$preg = '/^([A-Za-z0-9]| (?! )){8,12}/';

foreach ($strs as $str) {
    var_dump(preg_match($preg, $str));
}

return;

It will return:

int(1)
int(1)
int(0)