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f#deedle

F# deedle how to convert frame to list of tuples


say I have a Frame of the following,

type Person = 
    { Name:string; Age:int; Comp1:float; Comp2:float }

let peopleRecds = 
    [ { Name = "Joe"; Age = 51; Comp1=12.1; Comp2 =20.3 }
      { Name = "Tomas"; Age = 28; Comp1=1.1; Comp2 =29.3 }
      { Name = "Eve"; Age = 2; Comp1=2.1; Comp2 =40.3 }
      { Name = "Suzanne"; Age = 15; Comp1=12.4; Comp2 =26.3} ]
let peopleList = Frame.ofRecords peopleRecds

How do i convert peopleList to a list of tuples?


Solution

  • For creating a tuple can use FSharpValue.MakeTuple

    Then you need to specify a type or tuple:

    open Microsoft.FSharp.Reflection
    
    type Person =  { Name:string; Age:int; Comp1:float; Comp2:float }
    
    let peopleRecds = 
        [ { Name = "Joe"; Age = 51; Comp1=12.1; Comp2 =20.3 }
          { Name = "Tomas"; Age = 28; Comp1=1.1; Comp2 =29.3 }
          { Name = "Eve"; Age = 2; Comp1=2.1; Comp2 =40.3 }
          { Name = "Suzanne"; Age = 15; Comp1=12.4; Comp2 =26.3} ]
    
    let peopleList = Frame.ofRecords peopleRecds   
    
    let toListOfTuple (frame:Frame<_,_>) tupleType = 
        frame.Rows
        |> Series.mapValues(Series.values >> Seq.toArray)
        |> Series.mapValues(fun x -> FSharpValue.MakeTuple(x, tupleType))
        |> Series.values
        |> Seq.toList
    
    let tupleType = typeof<(string*int*float*float)>
    
    (peopleList, tupleType)
    ||> toListOfTuple 
    |> List.iter(printfn "%A")
    

    Print:

    ("Joe", 51, 12.1, 20.3)
    ("Tomas", 28, 1.1, 29.3)
    ("Eve", 2, 2.1, 40.3)
    ("Suzanne", 15, 12.4, 26.3)