[eschwartz]

Using list_difference() [see here]:

list_difference(list1, list2, separator) – return a list made by removing from list1 any item found in list2, using a case-insensitive compare. The items in list1 and list2 are separated by separator, as are the items in the returned list.

PHP Code:

list_difference(
    field('tags'),
    "comma,separated,list,of,excluded,tags",
    ","
) 


will return a new list, that contains only the items in list1 (tags field) that are not excluded using list2 ("comma,separated,list,of,excluded,tags")

So try this:

PHP Code:

program:

str_in_list(
    list_difference(
        field('tags'),
        "comma,separated,list,of,excluded,tags",
        ","
    ),
    ",",
    "First",
    "First",
    ""
) 


It appears that the "PHP" BBCode is better than the "CODE" BBCode for this CODE.