Pick R←X⊃Y

Y may be any array.

X is a scalar or vector of indices of Y.

R is an item selected from the structure of Y according to X.

Elements of X select from successively deeper levels in the structure of Y. The items of X are simple integer scalars or vectors which identify a set of indices, one per axis at the particular level of nesting of Y in row-major order. Simple scalar items in Y may be picked by empty vector items in X to any arbitrary depth.

⎕IO is an implicit argument of Pick.

Examples

      G←('ABC' 1)('DEF' 2)('GHI' 3)('JKL' 4)

      G←2 3⍴G,('MNO' 5)('PQR' 6)

      G
  ABC  1   DEF  2   GHI  3
  JKL  4   MNO  5   PQR  6

    ((⊂2 1),1)⊃G
JKL

      (⊂2 1)⊃G
 JKL  4

      ((2 1)1 2)⊃G
K

      (5⍴⊂⍳0)⊃10
10