IBM Watson Assistant, how can I remove multiple items from an array?

Question

I have a list unmentioned_colors = ["red", "green", "blue", "yellow"] If I mention multiple colors, I want to update my unmentioned_colors array, removing the ones that I mentioned. So if I write "red green" I want to remove them from unmentioned_colors where it will become ["blue", "yellow"]

I tried unmentioned_colors = "<? $unmentioned_colors.removeValue(@colors.values) ?>" But it is not working. How can I remove multiple @colors from my array?

Answer 1

To remove all @colors items from $unmentioned_colors one should set a context variable $_bool_listchanged as shown here:

_bool_listchanged = "<? $unmentioned_colors.removeAll(@colors.values) ?>" .

This solution does not require a loop and works because underneath the hood Watson Assistant uses Java to manipulate items in the contact. So on this array we have the method removeAll which we can call from Java.