For me this worked.
$string = 'help';
#First, str_pad() with unique character.
$string = str_pad($string, 10, "*", STR_PAD_BOTH);
#$string = '***help***';
#Second, str_replace with ' '
$string = str_replace("*", " ", $string);
For me this worked.
$string = 'help';
#First, str_pad() with unique character.
$string = str_pad($string, 10, "*", STR_PAD_BOTH);
#$string = '***help***';
#Second, str_replace with ' '
$string = str_replace("*", " ", $string);