Any collection that implements IEnumerable is fairly easy to convert to a sequence. This is because, by definition, IEnumerable is a sequence in F#. Since strings and arrays implement IEnumerable, they can be processed without any explicit conversion into functions by using the casting operators on a sequence as seen next:
let seqFromArray = [| 1 .. 10 |] :> seq<int> let seqFromArray = [| 1 .. 10 |] |> Seq.ofArray
Note
The challenge here might be in a case when such functions return a sequence; you may need to convert the returned elements back into an array using Array.ofSeq or Seq.toArray.
You also see the type casting operators in the preceding statements. The operator :> converts a type to another type that is higher in the hierarchy. Its counterpart, the :?> operator, converts a type to a different type that is lower in the hierarchy.