f# - looping through array

Question

I have decided to take up f# as my functional language.

My problem: Give a bunch of 50digits in a file, get the first 10 digits of the sum of each line. (euler problem for those who know)

for example (simplified): 1234567890

The sum is 45
The first "ten" digits or in our case the "first" digit is 4.

Heres my problem, I read my file of numbers, I can split it using "\n" and now i have each line, and then I try to convert it to an char array, but the problem comes here. I can't access each element of that array.

let total =
    lines.Split([|'\n'|])
    |> Seq.map  (fun line -> line.ToCharArray())
    |> Seq.take 1
    |> Seq.to_list  
    |> Seq.length

I get each line, convert it to array, i take the first array (for testing only), and i try to convert it to list, and then get the length of the list. But this length is the length of how many arrays i have (ie, 1). It should be 50 as thats how many elements there are in the array.

Does anyone know how to pipeline it to access each char?

Answer 1

Seq.take is still returning a seq<char array>. To get only the first array you could use Seq.nth 0.

Answer 2

My final answer:

let total =
    lines.Split([|'\n'|])
    |> Seq.map (fun line -> line.ToCharArray() |> Array.to_seq)      
    |> Seq.map (fun eachSeq -> eachSeq 
                               |> Seq.take 50 //get rid of the \r
                               |> Seq.map (fun c -> Double.Parse(c.ToString()))
                               |> Seq.skip 10
                               |> Seq.sum                                
                               )
    |> Seq.average

is what i got finally and it's working :).

Bascially after I convert it to charArray, i make it a sequence. So now i have a sequence of sequence. Then I can loop through each seqquence.