Question

How can I get hold of a column or row of a 2D Array in F# (ideally as a 1D array, but a Seq would be nice as well). Obviously I could write it myself, but you would think it must be already provided…

E.g. I am after built-in equivalent for:

let row i array = seq { for j in 0 .. (Array2D.length2 array)-1 do yield array.[i,j]}

Answer 1

I don’t think there is a built-in function for this.

You could slice the array and flatten the slice using Seq.cast:

let row i (arr: 'T[,]) = arr.[i..i, *] |> Seq.cast<'T>