[wp-hackers] Changing two variables listed in apply_filters hook

[Ted Balaban]

When the apply_filters hook has 2 variables how 
do you change the second variable in a plugin?

For example:
apply_filter ('get_categories', $categories, $r);

I know what to do for one variable.  Create a function
with the specified variable as an argument and in the
return statement.  Call add_filter.

For example:
function test_function ($test)  {
  $test =  .......
  return $test;
}
add_filter ('hook', 'test_function');

Any help is appreciated.

tsbalaban