PHP: How can I remove from String the last word?

How can I remove, with PHP, the last word from a String?

For example the string "Hi, I'm Gian Marco" would become "Hi, I'm Gian".

Answer

try with this :

$txt = "Hi, I'm Gian Marco";
$str= preg_replace('/Ww+s*(W*)$/', '$1', $txt);
echo $str

out put

Hi, I'm Gian