Educating about C# and F#

Seq.average - F#

Lets examine Seq.average.

Seq.average: returns the average of the elements in the sequence. ~ FSharp.Core

let main argv =
    let seq = seq { 1.0 .. 4.0 }
    let average = seq |> Seq.average
    printfn "%f" average

We have a sequence consisting of [1.0; 2.0; 3.0. 4.0], running this prints out 2.5000, which is the correct average.

Pretty self explanatory, the only gotcha is it doesn’t support int as a data type.

Seq.average supports any type that:

  • has (+) operator
  • has static property Zero
  • has static member DivideByInt.

int fulfills everything but the last requirement.

int is not supported because some numbers divided by an int come out as a float instead of an int. ie: 5 / 2 = 2.5.

Since the input type int is different than the output type float, it doesn’t pass the third case, therefore, can’t be used in Seq.average.