PHP 正则表达式 - 可选 Unicode UTF-8 字符（Ø？）不起作用

Question

I have string where it contains Ø character but not always:

$pattern = '/Ø?\d+[a-z-]+Ø?\d+/i';
if (preg_match($pattern, 'Ø66-SX-76', $matched)) {
    print_r($matched);
}
if (preg_match($pattern, '58-SX-72', $matched)) {
    print_r($matched);
}
if (preg_match($pattern, 'Ø66-SX-Ø76', $matched)) {
    //only this one matches
    print_r($matched);
}

These are a basic example of the string I am processing.

Can somebody explain why the first 2 cases are not matching?

When I try on regexpal.com this pattern is working for all case, but on PHP it is not working

Answer 1

You can instruct the regex engine to treat the input string as utf-8. Add the u modifier at the end:

$pattern = '/Ø?\d+[a-z-]+Ø?\d+/iu';

Answer 2

Thanks to @Joey, adding wrapping Ø in parantheses worked:

$pattern = '/(Ø)?\d+[a-z-]+(Ø)?\d+/i';