f may be any dyadic function. X and Y may be any arrays whose items are appropriate to function f.
The derived function is equivalent to YfX. The derived function need not return a result.
If left argument X is omitted, the right argument Y is duplicated in its place, that is:
f⍨Y ←→ Y f⍨Y
Examples
N
3 2 5 4 6 1 3
N/⍨2|N
3 5 1 3
⍴⍨3
3 3 3
mean←+/∘(÷∘⍴⍨) ⍝ mean of a vector
mean ⍳10
5.5
The following statements are equivalent:
F/⍨←I F←F/⍨I F←I/F
Commute often eliminates the need for parentheses