WEB+DB PRESS Vol.67 第2章 F#

calc

let ret1 = List.zip [0..4] [10;20;30;40;50];;
let mul (i, x) = x * i;;
let ret2 = List.map mul ret1;;
let calc xs = List.fold (fun acc value -> acc + value) 0 (List.map mul (List.zip [0..4] xs));;
calc [10;20;30;40;50];;

zip_map_fold

List.zip [10;20;30;40;50] [0..4] 
  |> List.map (fun x -> fst x * snd x) 
  |> List.fold (fun acc value -> acc + value) 0;;