¨ — Eachf¨Y applies f to each item and collects the returned values in Y’s shape. On atoms it calls f directly.
≢¨(1 2⋄ 3 4 5) ⍝ 2x 3x
X f¨Y pairs items using leading agreement.
1 2+¨10 ⍝ 11 12
On empty arguments, Each calls f once using prototypes. Prototype mode permits Pick to select fill.
{100⊃'abc'}¨⍬ ⍝ ''
Other errors and explicit output remain observable in that call.