Lesson 5 Step 4

[bit4bit]

hi i newbie with ocaml..

I do this solutions.. but nothing say me that is it the answer:

let up = let up = Char.uppercase in
let big_xy = List.map up xy in
let big_ab = List.map up ab in
big_ab @ big_xy

val up : char list = ['A'; 'B'; 'X'; 'Y']

or

let up = 
let big_xy = List.map Char.uppercase xy in
let big_ab = List.map Char.uppercase ab in
big_ab @ big_xy

val up : char list = ['A'; 'B'; 'X'; 'Y']

or

let up =
List.map Char.uppercase ab @ List.map Char.uppercase xy

val up : char list = ['A'; 'B'; 'X'; 'Y']

thanks..
for any answer.

[cagdasbozman]

All your answer is correct and equivalent. There is no better answer in your case.
If I had to choose, I'll take the second one, then the third one and finally the first answer.

[bit4bit]

thanks..
but the lesson not complete..

[guido4000]

I would assume the simple solution to be the following:

let up = Char.uppercase in
  let big_xy = List.map up xy in
  let big_ab = List.map up ab in
  big_ab @ big_xy

[cdaringe]

Lesson 5 Step 4 introduces concepts not covered before the step.

1. syntax w.r.t. multiple let expressions in a function are not covered (where do ins go? ;s?)
2. @ symbol/operator? (still doing these exercises) is not covered