- preg_replace: documentation ( source)
- setlocale: documentation ( source)
<?php
echo preg_replace('/(*UCP)\b/', '<$0>', 'and рублей').PHP_EOL;
echo preg_replace('/(*UTF8)\b/', '<$0>', 'and рублей').PHP_EOL;
echo preg_replace('/\b/u', '<$0>', 'and рублей').PHP_EOL;
echo setlocale();