how to change every character in a string EXCEPT spaces to X's

Can someone tell me how to change every character in a string EXCEPT spaces to X's in PHP?

Example:


"123 Hello Plaza Snottingham Hants PO12 345"

would become:

"XXX XXX XXXX XXXXXXXXX XXXX XXXX XXX"

 

<?php
$string = '123 Hello Plaza Snottingham Hants PO12 345';
$regex = '/[^\s]/i';
$result = preg_replace($regex, 'X', $string);
echo $result;
?>

PHP:

 

That will also change tabs, newlines, etc., to X's which wasn't the spec.

$regex = '/ /';

PHP:

Though in real life I'd guess you want runs of spaces collapsed to a single X:

$regex = '/ +/';

PHP:

Incidentally I live in Snottingham Hants. You too?

 

The spec was pretty much every single character except spaces, so anything not a space should be an X I guess..