Sorting & Searching: ⎕ct←0 Index   <<   >>


 
i0←{⎕ct←0 ⋄ ⍺⍳⍵}

x←?1e6⍴0
cmpx 'x⍳x' 'x i0 x'  ⍝ selfie

y←(⍴x)⍴x
cmpx 'x⍳y' 'x i0 y'  ⍝ not selfie