Problem with regex?

Question

PHP

Can you please explain what is the problem?
I have a regular expression that returns 0

preg_match('/^[a-zA-Zа-яА-ЯёЁІіЇїЄєҐґ\']+$/', 'пример'));

and 1

preg_match('/^[a-zA-Zа-яА-ЯёЁІіЇїЄєҐґ\']+$/', 'example')

Why is there 0 in the first option?

Answer 1

You forgot the u flag : you have a string in utf-8.