preg_match_all与所有主机名都不匹配

Question

Ok, I'm trying to get hostnames and i'm using this regex:

preg_match_all("/^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$/", 'google.com some text example.com', $matches);
print_r($matches[0]);

Matches should be:

google.com
example.com

but, the output is the first match only (google.com)

What i should change to get all matches please?

Answer 1

One cheap trick you could apply is to simply replace your anchors with a word boundary assertion:

preg_match_all("/\b(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])\b/", 'google.com some text example.com', $matches);
//               ^^                                                                                                         ^^

That would yield:

Array(
  [0] => google.com
  [1] => some
  [2] => text
  [3] => example.com
)

To filter out word without at least one period:

preg_match_all("/\b(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)+([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])\b/", 'google.com some text example.com', $matches);
//                                                                       ^
print_r($matches[0]);