How to replace/remove 4(+)-byte characters from a UTF-8 string in PHP?

Question

It seems like MySQL does not support characters with more than 3 bytes in its default UTF-8 charset.

So, in PHP, how can I get rid of all 4(-and-more)-byte character

Answer 1

Came across this question when trying to solve my own issue (Facebook spits out certain emoticons as 4-byte characters, Amazon Mechanical Turk does not accept 4-byte characters).

I ended up using this, doesn't require mbstring extension:

function remove_4_byte($string) {
    $char_array = preg_split('/(?3) {
            $char_array[$x] = "";
        }
    }
    return implode($char_array, "");
}