删除字符串中的所有单词“＃User＃，<br> <br>谢谢＃在'＃User＃'和”＃“之间提供”并从字符串中提取“＃User＃”

I need some regex that removes words as specified in title. I have tried below regex but it didn't worked. Also i want to extract "#User#" from given string - means starting with '#' and ending with '#' from string which don't contains any space.

preg_match_all("~#(.*?)#~", “#User#,<br><br>Thanks#For providing” , 
$wordReplaceArr_tmp);

Result of above code is below:

Output: User#,<br><br>Thanks

Expected result: "#User#"

If I got you right, you want the name(?) of the user between the first two hashtags and remove everything else. Your regex is greedy, means it captures more than it should. Add the hashtag to the "do not match" list and it will only capture anything UNTIL it finds another hashtag.

$str = '#User#,<br><br>Thanks#For providing';
preg_match_all('/#([^#]+)#/mis', $str, $matches);

print_r($matches);

The result of this code is the following:

Array
(
    [0] => Array
        (
            [0] => #User#
        )

    [1] => Array
        (
            [0] => User
        )

)

You can access the user now with $matches[1][0]