Ditto PHP:
php > var_export(preg_match("/\d/", "1"));
1
php > var_export(preg_match("/\d/", "۳"));
0 php > var_export(preg_match("/\d/", "1"));
1
php > var_export(preg_match("/\d/", "۳"));
0 php > var_export(preg_match("/\d/u", "۳"));