Code Golf
Given two lists only containing positive integers, return all items among these two lists that aren't contained in both of the lists.

## Rules
From the set definition:
> A set is a collection of definite distinct items.

* So you can assume the items in the input lists are always unique.
* You can also take input as a set if your language supports it.

## Test cases
[Here]( is a sample program that generates the test cases.
[1,2,3],[2,3,4] -> [1,4]
Top Answer Kotlin
# [Kotlin], 16 bytes


[Try it online!][TIO-k8z2em2a]

[TIO-k8z2em2a]: "Kotlin – Try It Online"
Answer #2 Julia 1.0
Lennart Jonsson
# [Julia 1.0], 24 bytes


Answer #3 APL (Dyalog Unicode)
# [APL (Dyalog Unicode)], 3 bytes

[Try it online!][TIO-k9kfg28t]

`∪` union `~` without `∩` intersection.

[APL (Dyalog Unicode)]:
[TIO-k9kfg28t]: "APL (Dyalog Unicode) – Try It Online"
Answer #4 CJam
# [CJam], 3 bytes


[Try it online!][TIO-k9hb52gb]

[TIO-k9hb52gb]: "CJam – Try It Online"
Answer #5 J
# [J](, 8 bytes

[Try it online!](

Concatenate minus intersection.

Simply concatenates (`,`) the two arguments and set-subtracts (`-.`) from it the intersection ($f(A,B)=A{\backslash}(A{\backslash}B)$ ; `[ -. -.`) of them.

edit: right after posting this, I realized there is a very clever 6-byte solution (I saw it after I checked the answers to this challenge on CGSE). I didn't come up with it myself so I won't count it towards my score, but I'm putting it here anyway.



Concatenate (`,`) A\B (`-.`) and B\A (`-. ~`)

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