Split R←↓[K]Y

Y may be any array. The axis specification is optional. If present, K must be a simple integer scalar or one-element vector. The value of K must be an axis of Y. If absent, the last axis is implied.

The items of R are the sub-arrays of Y along the Kth axis. R is a scalar if Y is a scalar. Otherwise R is an array whose rank is ¯1+⍴⍴Y and whose shape is (K≠⍳⍴⍴Y)/⍴Y.

Examples

      ↓3 4⍴'MINDTHATSTEP'
 MIND  THAT  STEP

      ↓2 5⍴⍳10
 1 2 3 4 5  6 7 8 9 10

      ↓[1]2 5⍴⍳10
 1 6  2 7  3 8  4 9  5 10