How to leave only Cyrillic in a string?

Question

PHP

Hello. I have the following problem. It is required to remove all characters from the string, except for spaces and Cyrillic. I do it like this:

$titleAttraction = "Красная площадь Red Square (Krasnaya ploshchad)";
$russianTitleAttraction = preg_replace("/[^а-я ]/", "" , $titleAttraction);
$russianTitleAttraction = trim($russianTitleAttraction);
echo $russianTitleAttraction;

Everything seems to be displayed correctly, but some characters are replaced by abbreviations in the form of a question mark , something like the following: If you display the original string on the screen, this does not happen. Please tell me what I'm doing wrong and how to fix it?
Thanks in advance to all who respond.

Answer 1

The file must be encoded in Unicode UTF-8 and in the regular expression /[^a-z ]/u