data=:'abracadabra'

   NB. whereas
   1j_2 # data
|domain error
|   1j_2    #data

   NB. I've often wanted
   _2 |. 1j2 # data
  a  b  r  a  c  a  d  a  b  r  a

   NB. because it aligns with

   3 ": i.~ data                      NB. index from left
  0  1  2  0  4  0  6  0  1  2  0

   3 ": i:~ data                      NB. index from right
 10  8  9 10  4 10  6 10  8  9 10

   duplicate =: (i: ~: i.)~
   duplicate data
1 1 1 1 0 1 0 1 1 1 1
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