⍬ Zilde

Zilde is a primitive constant, which contains an empty numeric vector. It is equivalent to ⍳0 or 0⍴0.

      X←⍬
      ⍴X
0
      X≡0⍴0
1
      X≡''
0
      ⎕DISPLAY ''     ⍝ Empty character vector
┌⊖┐
│ │
└─┘
      ⎕DISPLAY ⍬      ⍝ Empty numeric vector
┌⊖┐
│0│
└~┘
      3↑⍬
0 0 0