CODEWITHSUNDEEP
ocaml
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Reputation: 9140

How can I use the "label" version of List.nth in OCaml?

So basically I am writing some OCaml code like this:

let p_op p =
Show.show<op> p
|> Str.split (Str.regexp " +")
|> List.nth items 1           (items is the result of Str.split)
|> String.lowercase

So the problem is that how can I implicitly pass the result of Str.split to List.nth ?

if I know the label of List.nth, then I guess I can do this, 

List.nth ~num:1

But basically as I don't use Core, I just don't know how to get the label of List.nth could anyone give me some help?

Then probably I need to wrapper the List.nth with labels myself?

Upvotes: 1

Views: 104

Answers (1)

Jeffrey Scofield
Jeffrey Scofield

Reputation: 66823

The obvious place to look for this is in ListLabels. But for whatever reason the parameters of ListLabels.nth aren't labelled!

You can use flip:

let flip f x y = f y x

... |> flip List.nth 1 |> ...

flip is defined in OCaml Batteries Included as BatPervasives.flip (and also in Core).

Upvotes: 4

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