PHP | wrap the last word of a string in span

last_word_wrap.php

<?php
// Function to wrap last word in span
function last_word_wrap($string, $class = null) {
    $span = '<span';
    if( $class ) {
        $span .= ' class="' . $class . '"';
    }
    $span .= '>';
    $wrapped = preg_replace('/\s(\S*)$/', ' ' . $span . '$1', $string);
    $wrapped .= '</span>';
    return $wrapped;
}

That's much neater @elron, thank you! preg_replace always looks messy.

Thanks!
I wonder if there any performance advantage for preg_replace or explode/implode.
Anyway, I'm using it for short strings so it should be fine.