@Adám sure

> Write a function that takes a vector as its right argument and returns elements that occur only once in the vector.

Is it just me, or is this really similar to 2016-3 Statistics - Mode?

Oh, btw, we'll start 2 hours earlier, beginning in 2 weeks, 14 October.

golfed: ∊=⍥≢⌸⊆∪

Oof.

Needs an ⍤, to pass the edge cases

@ovs That only works on simple vectors.

{1=≢⍵}⌸⊢⍤⌿∪ would be the general solution (for all but scalars).

(1=⍧⍨)⍛⌿⍨

⊢~~∘≠⊢⍤/⊢

@ovs Hm, the problem spec doesn't require handling scalars.

@Adám But the test driver complains otherwise

@Adám Because of the ∊? So replacing ∊⊆ with ⊢⍤/ would fix it?

@dzaima (⊢⌿⍨1=⍧⍨ also using dzaima/APLs ⌿ being a guaranteed functiion)

@ovs Fixed. (Needs time to rebuild.)

@ovs ⊢⍤⌿ but yeah.

@Razetime That's really clever. Hopefully ⊢~~∘≠⍛/ in 19.0.

… which matches @ovs's golfed but limited solution.

Now we just need to extend dyadic ~ to high-rank arrays so we can do ⊢~~∘≠⍛⌿

is that already in extended

No, it has the previous definition of monadic f⍛g

Vision does have it.

vision. i haven't heard of it

ah, i see, there's a repository.

Shall we try the ⌸ approach without ∪?

Anything better than {⊃⊢⍤⌿/,⌿{⍺,⍨1=≢⍵}⌸⍵}?

{⊃,/{⊂(1=≢⍵)/⍺}⌸⍵}?

And as {⊃,/{⊂⍺⌿⍨1=≢⍵}⌸⍵} that is even better. Nice!

Ooh, but fails on high-rank, due to ,/ not being a general merge.

Oh well, I guess that's enough.

See you next week for 2016-6: Shorter Ones to the Front, and don't forget that we'll start 2 hours earlier, beginning in 2 weeks, 14 October.

∊~⍨.⊣⌸

stolen - I'm sure ngn posted that as a solution ages ago