php true multi-byte string shuffle function? - php

Question

I have a unique problem with multibyte character strings and need to be able to shuffle, with some fair degree of randomness, a long UTF-8 encoded multibyte string in PHP without dropping or losing or repeating any of the characters.
In the PHP manual under str_shuffle there is a multi-byte function (the first user submitted one) that doesn't work: If I use a string with for example all the Japanese hiragana and katakana of string length (ex) 120 chars, I am returned a string that's 119 chars or 118 chars. Sometimes I've seen duplicate chars even though the original string doesn't have them. So that's not functional.
To make this more complex, I also need to include if possible Japanese UTF-8 newlines and line feeds and punctuation.
Can anyone with experience dealing in multiple languages with UTF-8 mb strings help? Does PHP have any built in functions to do this? str_shuffle is EXACTLY what I want. I just need it to also work on multibyte chars.
Thanks very much!

Answer 1

Try splitting the string using mb_strlen and mb_substr to create an array, then using shuffle before joining it back together again. (Edit: As also demonstrated in #Frosty Z's answer.)
An example from the PHP interactive prompt:
php > $string = "Pretend I'm multibyte!";
php > $len = mb_strlen($string);
php > $sploded = array();
php > while($len-- > 0) { $sploded[] = mb_substr($string, $len, 1); }
php > shuffle($sploded);
php > echo join('', $sploded);
rmedt tmu nIb'lyi!eteP
You'll want to be sure to specify the encoding, where appropriate.

Answer 2

This should do the trick, too. I hope.
class String
{
public function mbStrShuffle($string)
{
$chars = $this->mbGetChars($string);
shuffle($chars);
return implode('', $chars);
}
public function mbGetChars($string)
{
$chars = [];
for($i = 0, $length = mb_strlen($string); $i < $length; ++$i)
{
$chars[] = mb_substr($string, $i, 1, 'UTF-8');
}
return $chars;
}
}

Answer 3

I like to use this function:
function mb_str_shuffle($multibyte_string = "abcčćdđefghijklmnopqrsštuvwxyzžß,.-+'*?=)(/&%$#!~ˇ^˘°˛`˙´˝") {
$characters_array = mb_str_split($multibyte_string);
shuffle($characters_array);
return implode('', $characters_array); // or join('', $characters_array); if you have a death wish (JK)
}
Split string into an array of multibyte characters
Shuffle the good guy array who doesn't care about his residents being multibyte
Join the shuffled array together into a string
Of course I normally wouldn't have a default value for function's parameter.