To deal a single card from a deck, we might use the following dfn:
deal ← { (?≢⍵) I ⍵ }
deck ← ↑,⍳13 4
disp deal deck
7♢
We can do the same tacitly using a fork and a jot:
deal ← ?∘≢ I ⊢
disp deal deck
4♡
↓disp 5 deal deck
9♡ J♣ K♢ 2♡ T♠