lookup error in custom function

[Harriet Bazley]

I have a simple custom function that uses PipeDream's lookup() function
to look for various hard-coded values in the first array passed to it
and return the sum of the corresponding values in the second input
array.

...function("edibles","categories:array","prices:array")
...lookup(C7,@categories,@prices)
...lookup(C8,@categories,@prices)
...lookup(C9,@categories,@prices)
...lookup(C10,@categories,@prices)
...result(sum(A7A10))


How do I deal with the case when one or more of these values are not
present in the input at all without returning an error? I just want the
slot in question to be assigned the value 0.

--
Harriet Bazley == Loyaulte me lie ==

A bachelor is footloose and fiancee free.