∪
¶Unique works on major cells:
matrix←6 2⍴2 7 1 8 2 8 1 8 2 8 4 5
matrix
∪matrix
⍸
and monadic functions ⍋
and ⍒
¶Interval index, Grade up, and Grade down use Total Array Ordering to work on the major cells:
'Adam' 'Jay' 'Roger'⍸2 3⍴'APLXYZ' ⍝ scalars of a vector
(3 5⍴'Adam Jay Roger')⍸2 5⍴'KarenGitte' ⍝ vectors of a matrix
vector←0 0J2 ¯1 'A' 1 0J¯2
⍋vector
{(⊂⍋⍵)⌷⍵}vector ⍝ new special-cased idiom
{(⊂⍒⍵)⌷⍵}vector ⍝ new special-cased idiom