FirstOrDefault In F#

Question

How to write FirstOrDefault Linq Query in F#? Can I use linq to sql in F# in totally?

Answer 1

Note that a more idiomatic approach within F# would probably be to use something along the lines of Seq.tryFind rather than to use the LINQ operators, although it's not a drop in replacement since it returns an option value.

Answer 2

Because the Seq module already has a head function of type seq<'a> -> 'a, I would define a function tryHead with signature seq<'a> -> option<'a>:

module Seq =
    let tryHead (ls:seq<'a>) : option<'a>  = ls |> Seq.tryPick Some

using it as:

[1; 2; 3] |> Seq.tryHead