f may be any monadic function. Y may be any array, each of whose items are separately appropriate to function f.
The derived function applies function f separately to each item of Y. The derived function need not return a result. If a result is returned, R has the same shape as Y, and its elements are the items produced by the application of function f to the corresponding items of Y.
If Y is empty, the prototype of R is determined by applying the operand function once to the prototype of Y.
G←('TOM' (⍳3))('DICK' (⍳4))('HARRY' (⍳5))
⍴G
3
⍴¨G
2 2 2
⍴¨¨G
3 3 4 4 5 5
+⎕FX¨('FOO1' 'A←1')('FOO2' 'A←2')
FOO1 FOO2