PHP Equivalent function call for Perl Translation?

Perl Function -
$x='ABCD234cl59';
$x=~tr/0-9//cd;
print $x;
yields 23459

$y='ABCD234cl59';
$y=~tr/A-Za-z//cd;
print $y;
yields ABCDcl

Is there a simple one liner for php that is equivalent to the above example in perl?
I've been trying to find something for a while and unable...
Thanks in Advance.

 

Not sure if you are looking for this:

http://uk3.php.net/strtr

Jay