How to apply or map a list of functions to a list of data?

Use PadRight with the cyclical padding setup:

funcs = {f1, f2, f3};
data = Range[1, 20];
MapThread[#1[#2] &, {PadRight[funcs, Length@data, funcs], data}]

or

MapThread[Compose, {PadRight[funcs, Length@data, funcs], data}]

{f1[1], f2[2], f3[3], f1[4], f2[5], f3[6], f1[7], f2[8], f3[9], f1[10], f2[11], f3[12], f1[13], f2[14], f3[15], f1[16], f2[17], f3[18], f1[19], f2[20]}


Here's how you can do it in a simple way:

functionMap[funcs_List, data_] := Module[{fn = RotateRight[funcs]}, 
    First[(fn = RotateLeft[fn])][#] & /@ data]

Use it as:

functionMap[{f1, f2, f3}, Range[20]]
(* {f1[1], f2[2], f3[3], f1[4], f2[5], f3[6], f1[7], f2[8], f3[9], f1[10],
    f2[11], f3[12], f1[13], f2[14], f3[15], f1[16], f2[17], f3[18], f1[19], f2[20]} *)


MapIndexed[{f1, f2, f3}[[Mod[First@#2, 3, 1]]][#1] &, data]

does what you want (thanks to Sjoerd for pointing out a silly inefficiency).

Tags:

List Manipulation

Recent Posts