print ~"3"; 
print pack("c",~ord("3"));

# Or...

print ~3
print unpack("L", ~"\x00\x00\x00\x03");

##</code><code>##

$x = "3"; print ~$x; # This is...
$x = 3;   print ~$x; # Not the same as this... 
$x .= ""; print ~$x; # But, after stringification, it is.