PHP regular match for strings

This article mainly introduces PHP for the string of regular matching, interested in the friend's reference, I hope to be helpful to everyone.

The implementation method is as follows:

/** * Is_external_link detects if string contains outer chain * @param string $text literal * @param string $host domain name * @return Boolean    false has an outer chain true No outer chain */function all_external_link ($text = ", $host =") {  if (empty ($host)) $host = $_server[' http_host '];  $reg = '/http (?: S?): \ /\/((?: [A-za-z0-9-]+\.) +[a-za-z]{2,4})/';  Preg_match_all ($reg, $text, $data);  $math = $data [1];  foreach ($math as $value) {    if ($value! = $host) return false;  }  return true;}

Summary : The above is the entire content of this article, I hope to be able to help you learn.

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