php使用通配符查找并替换使用字符串

I have strings in my html like this >> &rf=238255238255238255

So thats >> &rf= (and 18 random digits)

How do I find that with a view to replacing it with ... ?

My own &rf=0101010101010101

Well, you can capture it using regex and replace it whatever value you want.

Your regex will be "/(?<=&rf=)\\d+/"

$re = "/(?<=&rf=)\\d+/"; 
$str = ">> &rf=238255238255238255"; 
$subst = ""; 

$result = preg_replace($re, $subst, $str);

See Demo here.