仅限正则表达式：数字，字母和重音符号

I need to filter string to return only "numbers, letters and letters with accents" using PHP.

I've tried many different regex and I could not.

The closest I got was:

$string = 'Você está bem? 123 # ! @ ...';
echo preg_replace('/[^\w\s+$]/', '_', $string);

// Return: Voc__ est__ bem_ 123 _ _ _ ___
// But I need to return: Você_está_bem_123 _ _ _ ___

Can someone help me? I tried to solve it out for hours, even looking for other questions here.

Add a /u modifier:

$string = 'Você está bem? 123 # ! @ ...';
echo preg_replace('/[^\w\s+$]/u', '_', $string);
                              ^

See this IDEONE demo

More about the /u modifier in SO regex documentation:

Pattern and subject strings are treated as UTF-8.