What should the regular expression look like in my case?

Question

PHP

What should the regular expression look like?
There is a line

10 000 руб
12 000 руб

preg_replace('/[^\d]/', '', $string);
The essence of the question is that I need to get the number only from the first line, the second is simply ignored. But I can’t say for sure whether there is a line break there, since I get the line at the time of parsing.

Answer 1

preg_replace('/^([\s\d]+).*/is', '$1', $str);
then you can remove the spaces
preg_replace('/\s+/', '', $str);

Answer 2

preg_replace('/^(\d+)\s(\d+).*/s', '$1$2', $str);