Last word of string UpperCase

[rienh]

Hello all, I try to accomplish the following.
I have a string like: “volkswage n-golf-gti” **
And I want it to change the string into:
“Volkswage n Golf GTI” (last part completely uppercase)

But I have some difficulties understanding preg_replace.
Right now I have the following code:

<?php 
$string = 'volkswagen-golf-gti'; 
$string2 = ucwords(str_replace('-', ' ', $string)); 
$string2 = preg_replace("/\s+\S+$/e", "strtoupper('\\1')", $string2); 
echo $string2; 
?>

Without line 4 enabled, the result of the echo $string2 is:
Volkswagen Golf Gti (is wrong, last part is not completely uppercase)

With line 4 enabled, the last part of the $string is removed
so echo $string2 gives me :
Volkswagen Golf
How can I change the code so it select the last part of $string2 and makes that part uppercase? So the result of echo $string2; will be:
Volkswagen Golf GTI

** $string can be anything, not only volkswagen-golf-gti

[rienh]

Thanks to the solution of NoDog for providing me the solution, and solving my problem. The following code, did do the trick for me.

$var = 'volkswagen-golf-gti';
$regexp = array(
   '/-/' => ' ',
   '/.*/e' => 'ucwords("$0")',
   '/\b\S+$/e' => 'strtoupper("$0")'
);
$var2 = preg_replace(array_keys($regexp), $regexp, $var);
echo $var2;

[kovik]

This could have been done without regex. Assuming that the delimiter between your words is a space, you break the string apart, set the last word to uppercase, and glue the string back together. I just built a quick little function for it. No regex, just array manipulation.

Function:

function last_word_uppercase($sentence, $delimiter = ' ') {
    $words = explode($delimiter, $sentence);
    if (!empty($words)) {
        $lastWord = array_pop($words);
        $words[] = strtoupper($lastWord);
        return implode($delimiter, $words);
    }
 
    return strtoupper($sentence);
}

Usage:

$str = 'This is a sentence.';
echo last_word_uppercase($str);

Result:

This is a SENTENCE.