php实现使用正则将文本中的网址转换成链接标签_php技巧

function text2links($str='') {
if($str=='' or !preg_match('/(http|www\.|@)/i', $str)) { return $str; }
$lines = explode("\n", $str); $new_text = '';
while (list($k,$l) = each($lines)) {
// replace links:
$l = preg_replace("/([ \t]|^)www\./i", "\\1http://www.", $l);
$l = preg_replace("/([ \t]|^)ftp\./i", "\\1ftp://ftp.", $l);
$l = preg_replace("/(http:\/\/[^ )\r\n!]+)/i",
"\\1">\\1\">\\1>", $l);
$l = preg_replace("/(https:\/\/[^ )\r\n!]+)/i",
"\\1">\\1\">\\1>", $l);
$l = preg_replace("/(ftp:\/\/[^ )\r\n!]+)/i",
"\\1">\\1\">\\1>", $l);
$l = preg_replace(
"/([-a-z0-9_]+(\.[_a-z0-9-]+)*@([a-z0-9-]+(\.[a-z0-9-]+)+))/i",
"\\1">mailto:\\1\">\\1>", $l);
$new_text .= $l."\n";
}
return $new_text;
}