php用正则表达式去除空白行代码

$str = preg_replace("/(s*?r?ns*?)+/","n",$str);

$str = preg_replace('/($s*$)|(^s*^)/m', '',$str);

$newhtml=preg_replace("/(r?n)\1+/","\1",$newhtml)；

echo preg_replace('/($s*$)|(^s*^)/m', '', $str); 完美解决:victory:

$a = 'gdgdga

gagda
faf

fefe

fefe';
echo preg_replace('/(r?n)\1+/',"nn",$a);