I have a very simple function which produces a single array, how do I get this to display in the template?
I mean very simple like:

function DoThis() {
$a = 1;
}
how do i get $a to populate the $DoThis holder in the template?
push->
or just a staight echo ?? all help appreciated.

Assuming the function is accessible from the template you can just have the function return the array
function DoThis() {
return $a = 1;
}