Hello everybody, a question about expressions and arrays here. I have

jpheh, consider applying the append function after the merge. To illustrate: apply(fn!tostring, apply(fn!append, merge({"a", "b", "c"}, {1, 2, 3}))) returns: a1, b2, c3. Whereas: apply(fn!tostring, merge({"a", "b", "c"}, {1, 2, 3})) returns: a, b, c. This demonstrates that tostring was being passed an array when we apply the append, but was being passed multiple distinct elements when just using the merge. As you correctly state that "the apply function treats the result of a merge as individual arguments instead of a single array object when calling my expression.", we can use an applied append to combine the merged distinct elements into an array.

For this, we can simply pass two arrays to append function of Appian before using it in apply. Your expression will be like apply(fn!yourFunction,append(array1,array2)).

I think what want is can be achieved by apply(fn!yourFunction,append(megre(array1,array2)))

mschmitt: I'm not sure I follow what you mean by using the property function. It requires design time knowledge of the field name before it will work meaning I'd have to have an object specific version of the function.
joshl: I have an several arrays of user IDs (the number of arrays is dynamic). I need to check if all the userIDs at index X across all arrays are active. Your suggestion of using the append function is a good one however I've already tried it and it still produces the same error - the function is seeing 2 individual arguments instead of 1 array argument.
sachinr: Thanks for the suggestion but as above, I've already tried that and I'm still getting the same error.
While I have already created a work around it is not as generic, useful or portable as I would like. Thanks for all your help everybody but it looks like this is going to be a "doesn't work" issue for the time being.

jpheh, did you try applying the append, as in my comment above? apply(fn!yourFunction, apply(append(merge(array1,array2)))). My tests show that this will pass in arrays to your function instead of individual arguments.

Sorry, I assumed you would have some sort of list of potential field names in advance; if the field names are potentially unlimited or arbitrary, then my prior suggestion doesn't work. (The assumption I had been making was that you had, let's say, 4 different CDT types and they all had a specific "user IDs" field and these aren't likely to change much in the future.)

Jackm829: Yes, I tried using the append function. Perhaps it has to do with the type in the array but when I test it using userIDs (instead of string) I still receive an error about an incompatible number of parameters.

Its not a big issue, you just have to convert that userIDs to user by using touser Appian Function. So, final expression will be : apply(rule!yourRule, touser(append(merge(array1,array2))))
I have tested it. It will work fine.