How to build a regular expression correctly?

Question

Regular Expressions

Hello.
Over a year ago, I wrote an almost similar post. link
Now I need to change the task a bit.
You need to allow only Russian, English, Ukrainian and numbers.
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Slightly incorrectly stated the task.
You need to skip eng, rus, ukr and numbers and the symbol (-), and delete the rest!

Answer 1

Try like this:

<?php
$filtText = preg_replace('#[^a-zа-яїіё0-9]#iu','',$text);