How do you print raw UTF-8 characters from their numbers?

Say I wanted to print a ÿ (latin small y with diaeresis) from its Unicode/UTF-8 number of U+00FF or hex of c3 bf. How can I do that in PHP?

The reason is that I need to be able to create certain UTF-8 Characters is for testing in my regex and string functions. However, since I have less than 200 keys on my keyboard I开发者_如何学C can't type them - and since many times I am stuck in an ASCII only world - I need to be able to create them bases solely off of their ASCII safe, UTF-8 character code.

Note: In order for it show correctly in a browser I know that the first step is

header('Content-Type: text/html; charset=utf-8');

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well you have everything you need.
Hex values being recognized in double-quoted strings as well

echo "\xc3\xbf";

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Solution 1 with a small pack function

<?php

function chr_utf8($n,$f='C*'){
return $n<(1<<7)?chr($n):($n<1<<11?pack($f,192|$n>>6,1<<7|191&$n):
($n<(1<<16)?pack($f,224|$n>>12,1<<7|63&$n>>6,1<<7|63&$n):
($n<(1<<20|1<<16)?pack($f,240|$n>>18,1<<7|63&$n>>12,1<<7|63&$n>>6,1<<7|63&$n):'')));
}

echo chr_utf8(9405).chr_utf8(9402).chr_utf8(9409).chr_utf8(9409).chr_utf8(9412);

//Output ⒽⒺⓁⓁⓄ

Check it in https://eval.in/748062 …

Solution 2 with json_decode

<?php

$utf8_char='["';
for($number=0;$number<55296;$number++)
$utf8_char.='\u'.substr('000'.strtoupper(dechex($number)),-4).'","';
$utf8_char=json_decode(substr($utf8_char,0,-2).']');

echo $utf8_char[9405].$utf8_char[9402].$utf8_char[9409].$utf8_char[9409].$utf8_char[9412];

//Output ⒽⒺⓁⓁⓄ