php – 正则表达式删除http：//和www.来自网址

$urls = array(
    'https://site1.com','https://www.site2.com','http://www.site3.com','https://site4.com','site5.com','www.site6.com','www.site7.co.uk','site8.tk'
  );

我想删除http,https,：//和www.从这些字符串,以便输出看起来像这些.

$urls = array(
    'site1.com','site2.com','site3.com','site4.com','site6.com','site7.co.uk','site8.tk'
  );

我想出了这个解决方案.

foreach ($urls as $url) {
   $pattern = '/(http[s]?://)?(www.)?/i';
   $replace = "";
   echo "before: $url after: ".preg_replace('//$/','',preg_replace($pattern,$replace,$url))."n";
}

我想知道如何避免第二个preg_replace.有任何想法吗？