f may be any dyadic function. X and Y may be any arrays whose corresponding items (after scalar extension) are appropriate to function f when applied separately.
The derived function is applied separately to each pair of corresponding elements of X and Y. If X or Y is a scalar or single-element array, it will be extended to conform with the other argument. The derived function need not produce an explicit result. If a result is returned, R has the same shape as Y (after possible scalar extension) whose elements are the items produced by the application of the derived function to the corresponding items of X and Y.
If X or Y is empty, the operand function is applied once between the prototypes of X and Y to determine the prototype of R.
Examples
+G←(1 (2 3))(4 (5 6))(8 9)10 1 2 3 4 5 6 8 9 10 1⌽¨G 2 3 1 5 6 4 9 8 10 1⌽¨¨G 1 3 2 4 6 5 8 9 10 1⌽¨¨¨G 1 2 3 4 5 6 8 9 10 1 2 3 4↑¨G 1 4 5 6 8 9 0 10 0 0 0 'ABC',¨'XYZ' AX BY CZ