Más sobre Colecciones

Hasta ahora hemos visto el tipo de colección list, que es esencialmente una lista simplemente enlazada. La definición de list es similar a la que propusimos con MyList, pero

es general para cualquier tipo de dato
utiliza símbolos adecuados en lugar de etiquetas

type List<'T> = 
       | ([])  
       | ( :: )  of Head: 'T * Tail: 'T list

Como una lista es una unión discriminada, puede usarse tal cual cualquiera de ellas. Por ejemplo, se puede escribir una función para imprimir los elementos de una lista:

// loop through a list and print the values
let rec loopAndPrint aList =
    match aList with
    // empty list means we're done.
    | [] ->
        printfn "empty"

    // binding to head::tail.
    | x::xs ->
        printfn "element=%A," x
        // do all over again with the
        // rest of the list
        loopAndPrint xs

loopAndPrint []        

empty

let l = [1;2;3]

l |> loopAndPrint

element=1,
element=2,
element=3,
empty

Se puede acceder a distintos elementos de la lista a través de índices, aunque su uso no es generalizado. Si se utilizan las funciones Head y Tail para encontrar el primer elemento y el resto de la lista:

printfn "%A" l.Head
printfn "%A" (l |> List.head)
printfn "%A" l.Tail 
printfn "%A" (l |> List.tail) 

1
1
[2; 3]
[2; 3]

Acá podemos ver dos variantes de estas funciones:

Aquellas del tipo List. que provienen del módulo de listas de F#,
Métodos que un tipo de dato list.

En el caso de los métodos, vemos cómo F# provee también características asociadas a la programación orientada a objeto.

Hay que prestar atención a que una lista pueda ser vacía, porque en ese caso estos métodos devuelven una excepción:

printfn "%A" [].Head 

System.InvalidOperationException: The input list was empty.

   at Microsoft.FSharp.Collections.FSharpList`1.get_Head() in D:\a\_work\1\s\src\FSharp.Core\prim-types.fs:line 4072

   at <StartupCode$FSI_0010>.$FSI_0010.main@()

   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)

   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

printfn "%A" [].Tail

System.InvalidOperationException: The input list was empty.

   at Microsoft.FSharp.Collections.FSharpList`1.get_Tail() in D:\a\_work\1\s\src\FSharp.Core\prim-types.fs:line 4077

   at <StartupCode$FSI_0011>.$FSI_0011.main@()

   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)

   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

Usando la notación de listas, se pueden crear así:

let l = 3 :: [6;7]
printfn "%A" l

[3; 6; 7]

o concatenando dos listas:

let l2 = l @ [8;9]
printfn "%A" l2

[3; 6; 7; 8; 9]

Procesando listas

Como venimos insistiendo, la idea de las colecciones es poder procesarlas a través de un función, o una serie concatenada de funciones (usando piping) de forma tal de poder obtener el resultado adecuado.

Vimos que las funciones sobre colecciones se pueden clasificar de acuerdo al tipo de inputs y outputs de cada una de ellas. Detallando esta idea, en la siguiente imagen se ven algunos ejemplos de ellas, y qué tipos de inputs y outputs poseen (del libro Stylish F#, de Kit Easton):

La mayoría de estas funciones reciben como argumento una función y una lista, y devuelven una lista nueva con la transformación correspondiente. La función en general suele escribirse como una función anónima:

fun arguments -> expression

también conocidas como funciones lambda.

Trabajemos con un ejemplo para ir incorporando este concepto. Para ello, usaremos un par de tipos de datos Position y Player que describen algunas características de un jugador de fútbol:

type Position = GoalKeeper | Defender | Midfielder | Forward 

type Player =
    {
        Number: int 
        Name : string
        Team: string 
        Position: Position 
        Age: uint8 
    }

Obviamente, el ejemplo seguirá usando los siguientes ⭐️⭐️⭐️ :

let champions2022 = [
    // Los 3 arqueros de Argentina en Qatar 2022
    {Number = 23; Name = "Emiliano Martínez" ;  Team = "Aston Villa"; Position = GoalKeeper; Age = 30uy};
    {Number = 12; Name = "Gerónimo Rulli" ;  Team = "Villarreal"; Position = GoalKeeper; Age = 30uy};
    {Number = 1; Name = "Franco Armani" ;  Team = "River"; Position = GoalKeeper; Age = 36uy};
    // Los 9 defensores de Argentina en Qatar 2022
    {Number = 26; Name = "Nahuel Molina" ;  Team = "Atlético de Madrid"; Position = Defender; Age = 24uy};
    {Number = 4; Name = "Gonzalo Montiel" ;  Team = "Sevilla"; Position = Defender; Age = 25uy};
    {Number = 13; Name = "Cristian Romero" ;  Team = "Tottenham"; Position = Defender; Age = 24uy};
    {Number = 6; Name = "Germán Pezzella" ;  Team = "Betis"; Position = Defender; Age = 31uy};
    {Number = 19; Name = "Nicolás Otamendi" ;  Team = "Benfica"; Position = Defender; Age = 34uy};
    {Number = 25; Name = "Lisandro Martínez" ;  Team = "Manchester United"; Position = Defender; Age = 24uy};
    {Number = 8; Name = "Marcos Acuña" ;  Team = "Sevilla"; Position = Defender; Age = 31uy};
    {Number = 3; Name = "Nicolás Tagliafico" ;  Team = "Olympique de Lyon"; Position = Defender; Age = 30uy};
    {Number = 2; Name = "Juan Foyth" ;  Team = "Villarreal"; Position = Defender; Age = 24uy};
    // Los 8 mediocampistas de Argentina en Qatar 2022
    {Number = 7; Name = "Rodrigo De Paul" ;  Team = "Atlético de Madrid"; Position = Midfielder; Age = 28uy};
    {Number = 5; Name = "Leandro Paredes" ;  Team = "Juventus"; Position = Midfielder; Age = 28uy};
    {Number = 20; Name = "Alexis Mac Allister" ;  Team = "Brighton"; Position = Midfielder; Age = 23uy};
    {Number = 18; Name = "Guido Rodríguez" ;  Team = "Betis"; Position = Midfielder; Age = 28uy};
    {Number = 17; Name = "Alejandro Gómez" ;  Team = "Sevilla"; Position = Midfielder; Age = 34uy};
    {Number = 24; Name = "Enzo Fernández" ;  Team = "Benfica"; Position = Midfielder; Age = 21uy};
    {Number = 14; Name = "Exequiel Palacios" ;  Team = "Bayer Leverkusen"; Position = Midfielder; Age = 24uy};
    {Number = 16; Name = "Thiago Almada" ;  Team = "Atlanta United"; Position = Midfielder; Age = 21uy};
    // Los 6 delanteros de Argentina en Qatar 2022
    {Number = 11; Name = "Ángel Di María" ;  Team = "Juventus"; Position = Forward; Age = 34uy};
    {Number = 22; Name = "Lautaro Martínez" ;  Team = "Inter"; Position = Forward; Age = 25uy};
    {Number = 9; Name = "Julián Álvarez" ;  Team = "Manchester City"; Position = Forward; Age = 22uy};
    {Number = 21; Name = "Paulo Dybala" ;  Team = "Roma"; Position = Forward; Age = 29uy};
    {Number = 15; Name = "Ángel Correa" ;  Team = "Atlético Madrid"; Position = Forward; Age = 27uy};
    {Number = 10; Name = "Lionel Messi" ;  Team = "París Saint-Germain"; Position = Forward; Age = 35uy};
]

Definamos una función que nos permite recorrer la lista e imprimirla. Para eso usamos List.iter que, justamente, itera la lista y devuelve unit:

let almostPrettyPrintList l = 
    l 
    |> List.iter (fun elem -> printfn "%A" elem)

champions2022 
|> almostPrettyPrintList

{ Number = 23
  Name = "Emiliano Martínez"
  Team = "Aston Villa"
  Position = GoalKeeper
  Age = 30uy }
{ Number = 12
  Name = "Gerónimo Rulli"
  Team = "Villarreal"
  Position = GoalKeeper
  Age = 30uy }
{ Number = 1
  Name = "Franco Armani"
  Team = "River"
  Position = GoalKeeper
  Age = 36uy }
{ Number = 26
  Name = "Nahuel Molina"
  Team = "Atlético de Madrid"
  Position = Defender
  Age = 24uy }
{ Number = 4
  Name = "Gonzalo Montiel"
  Team = "Sevilla"
  Position = Defender
  Age = 25uy }
{ Number = 13
  Name = "Cristian Romero"
  Team = "Tottenham"
  Position = Defender
  Age = 24uy }
{ Number = 6
  Name = "Germán Pezzella"
  Team = "Betis"
  Position = Defender
  Age = 31uy }
{ Number = 19
  Name = "Nicolás Otamendi"
  Team = "Benfica"
  Position = Defender
  Age = 34uy }
{ Number = 25
  Name = "Lisandro Martínez"
  Team = "Manchester United"
  Position = Defender
  Age = 24uy }
{ Number = 8
  Name = "Marcos Acuña"
  Team = "Sevilla"
  Position = Defender
  Age = 31uy }
{ Number = 3
  Name = "Nicolás Tagliafico"
  Team = "Olympique de Lyon"
  Position = Defender
  Age = 30uy }
{ Number = 2
  Name = "Juan Foyth"
  Team = "Villarreal"
  Position = Defender
  Age = 24uy }
{ Number = 7
  Name = "Rodrigo De Paul"
  Team = "Atlético de Madrid"
  Position = Midfielder
  Age = 28uy }
{ Number = 5
  Name = "Leandro Paredes"
  Team = "Juventus"
  Position = Midfielder
  Age = 28uy }
{ Number = 20
  Name = "Alexis Mac Allister"
  Team = "Brighton"
  Position = Midfielder
  Age = 23uy }
{ Number = 18
  Name = "Guido Rodríguez"
  Team = "Betis"
  Position = Midfielder
  Age = 28uy }
{ Number = 17
  Name = "Alejandro Gómez"
  Team = "Sevilla"
  Position = Midfielder
  Age = 34uy }
{ Number = 24
  Name = "Enzo Fernández"
  Team = "Benfica"
  Position = Midfielder
  Age = 21uy }
{ Number = 14
  Name = "Exequiel Palacios"
  Team = "Bayer Leverkusen"
  Position = Midfielder
  Age = 24uy }
{ Number = 16
  Name = "Thiago Almada"
  Team = "Atlanta United"
  Position = Midfielder
  Age = 21uy }
{ Number = 11
  Name = "Ángel Di María"
  Team = "Juventus"
  Position = Forward
  Age = 34uy }
{ Number = 22
  Name = "Lautaro Martínez"
  Team = "Inter"
  Position = Forward
  Age = 25uy }
{ Number = 9
  Name = "Julián Álvarez"
  Team = "Manchester City"
  Position = Forward
  Age = 22uy }
{ Number = 21
  Name = "Paulo Dybala"
  Team = "Roma"
  Position = Forward
  Age = 29uy }
{ Number = 15
  Name = "Ángel Correa"
  Team = "Atlético Madrid"
  Position = Forward
  Age = 27uy }
{ Number = 10
  Name = "Lionel Messi"
  Team = "París Saint-Germain"
  Position = Forward
  Age = 35uy }

Interpolated strings

No es muy compacto… Podemos crear una función que nos permita imprimir el dato de cada jugador en forma más elegante. Vamos a usar interpolated strings para hacerlo. Un interpolated string es una cadena de caracteres que comienza con el símbolo $, y tiene el texto entre comillas dobles. En su interior se pueden usar los valores entre llaves {}.

let saludo = "Hola"

printfn "{saludo} Mundo"
printfn $"{saludo} Mundo"

{saludo} Mundo
Hola Mundo

let toStringPlayer player = 
    $"{player.Number}: {player.Name} ({player.Age}), {player.Position}, juega en {player.Team}"


let prettyPrintList l = 
    l
    |> List.iter (fun p -> printfn "%s" (toStringPlayer p))  

prettyPrintList champions2022       

Emiliano Martínez (30), GoalKeeper, juega en Aston Villa
Gerónimo Rulli (30), GoalKeeper, juega en Villarreal
Franco Armani (36), GoalKeeper, juega en River
Nahuel Molina (24), Defender, juega en Atlético de Madrid
Gonzalo Montiel (25), Defender, juega en Sevilla
Cristian Romero (24), Defender, juega en Tottenham
Germán Pezzella (31), Defender, juega en Betis
Nicolás Otamendi (34), Defender, juega en Benfica
Lisandro Martínez (24), Defender, juega en Manchester United
Marcos Acuña (31), Defender, juega en Sevilla
Nicolás Tagliafico (30), Defender, juega en Olympique de Lyon
Juan Foyth (24), Defender, juega en Villarreal
Rodrigo De Paul (28), Midfielder, juega en Atlético de Madrid
Leandro Paredes (28), Midfielder, juega en Juventus
Alexis Mac Allister (23), Midfielder, juega en Brighton
Guido Rodríguez (28), Midfielder, juega en Betis
Alejandro Gómez (34), Midfielder, juega en Sevilla
Enzo Fernández (21), Midfielder, juega en Benfica
Exequiel Palacios (24), Midfielder, juega en Bayer Leverkusen
Thiago Almada (21), Midfielder, juega en Atlanta United
Ángel Di María (34), Forward, juega en Juventus
Lautaro Martínez (25), Forward, juega en Inter
Julián Álvarez (22), Forward, juega en Manchester City
Paulo Dybala (29), Forward, juega en Roma
Ángel Correa (27), Forward, juega en Atlético Madrid
Lionel Messi (35), Forward, juega en París Saint-Germain

La lista se puede ordenar:

champions2022 
|> List.sort 
|> prettyPrintList

Franco Armani (36), GoalKeeper, juega en River
Juan Foyth (24), Defender, juega en Villarreal
Nicolás Tagliafico (30), Defender, juega en Olympique de Lyon
Gonzalo Montiel (25), Defender, juega en Sevilla
Leandro Paredes (28), Midfielder, juega en Juventus
Germán Pezzella (31), Defender, juega en Betis
Rodrigo De Paul (28), Midfielder, juega en Atlético de Madrid
Marcos Acuña (31), Defender, juega en Sevilla
Julián Álvarez (22), Forward, juega en Manchester City
Lionel Messi (35), Forward, juega en París Saint-Germain
Ángel Di María (34), Forward, juega en Juventus
Gerónimo Rulli (30), GoalKeeper, juega en Villarreal
Cristian Romero (24), Defender, juega en Tottenham
Exequiel Palacios (24), Midfielder, juega en Bayer Leverkusen
Ángel Correa (27), Forward, juega en Atlético Madrid
Thiago Almada (21), Midfielder, juega en Atlanta United
Alejandro Gómez (34), Midfielder, juega en Sevilla
Guido Rodríguez (28), Midfielder, juega en Betis
Nicolás Otamendi (34), Defender, juega en Benfica
Alexis Mac Allister (23), Midfielder, juega en Brighton
Paulo Dybala (29), Forward, juega en Roma
Lautaro Martínez (25), Forward, juega en Inter
Emiliano Martínez (30), GoalKeeper, juega en Aston Villa
Enzo Fernández (21), Midfielder, juega en Benfica
Lisandro Martínez (24), Defender, juega en Manchester United
Nahuel Molina (24), Defender, juega en Atlético de Madrid

Vemos que la lista aparece ordenada primero por número. En este caso, List.sort utiliza un comparador genérico para saber qué elemento está antes que otro. Sin embargo, la lista se puede ordenar de acuerdo a algún criterio usando List.sortBy:

champions2022 
|> List.sortBy (fun p -> p.Age)
|> prettyPrintList

Enzo Fernández (21), Midfielder, juega en Benfica
Thiago Almada (21), Midfielder, juega en Atlanta United
Julián Álvarez (22), Forward, juega en Manchester City
Alexis Mac Allister (23), Midfielder, juega en Brighton
Nahuel Molina (24), Defender, juega en Atlético de Madrid
Cristian Romero (24), Defender, juega en Tottenham
Lisandro Martínez (24), Defender, juega en Manchester United
Juan Foyth (24), Defender, juega en Villarreal
Exequiel Palacios (24), Midfielder, juega en Bayer Leverkusen
Gonzalo Montiel (25), Defender, juega en Sevilla
Lautaro Martínez (25), Forward, juega en Inter
Ángel Correa (27), Forward, juega en Atlético Madrid
Rodrigo De Paul (28), Midfielder, juega en Atlético de Madrid
Leandro Paredes (28), Midfielder, juega en Juventus
Guido Rodríguez (28), Midfielder, juega en Betis
Paulo Dybala (29), Forward, juega en Roma
Emiliano Martínez (30), GoalKeeper, juega en Aston Villa
Gerónimo Rulli (30), GoalKeeper, juega en Villarreal
Nicolás Tagliafico (30), Defender, juega en Olympique de Lyon
Germán Pezzella (31), Defender, juega en Betis
Marcos Acuña (31), Defender, juega en Sevilla
Nicolás Otamendi (34), Defender, juega en Benfica
Alejandro Gómez (34), Midfielder, juega en Sevilla
Ángel Di María (34), Forward, juega en Juventus
Lionel Messi (35), Forward, juega en París Saint-Germain
Franco Armani (36), GoalKeeper, juega en River

Quizás uno no necesita imprimir todos los datos de cada jugador:

champions2022 
|> List.sortBy (fun p -> p.Age)
|> List.map (fun p -> $"{p.Name} tiene {p.Age} años")
|> List.iter (fun s -> printfn "%s" s)

Enzo Fernández tiene 21 años
Thiago Almada tiene 21 años
Julián Álvarez tiene 22 años
Alexis Mac Allister tiene 23 años
Nahuel Molina tiene 24 años
Cristian Romero tiene 24 años
Lisandro Martínez tiene 24 años
Juan Foyth tiene 24 años
Exequiel Palacios tiene 24 años
Gonzalo Montiel tiene 25 años
Lautaro Martínez tiene 25 años
Ángel Correa tiene 27 años
Rodrigo De Paul tiene 28 años
Leandro Paredes tiene 28 años
Guido Rodríguez tiene 28 años
Paulo Dybala tiene 29 años
Emiliano Martínez tiene 30 años
Gerónimo Rulli tiene 30 años
Nicolás Tagliafico tiene 30 años
Germán Pezzella tiene 31 años
Marcos Acuña tiene 31 años
Nicolás Otamendi tiene 34 años
Alejandro Gómez tiene 34 años
Ángel Di María tiene 34 años
Lionel Messi tiene 35 años
Franco Armani tiene 36 años

Se puede buscar algún elemento de la lista con alguna característica particular:

champions2022
|> List.find (fun p -> p.Age = 21uy)

{ Number = 24\n Name = "Enzo Fernández"\n Team = "Benfica"\n Position = Midfielder\n Age = 21uy }

Number

Name Enzo Fernández

Team Benfica

Position

Midfielder

Age

champions2022
|> List.sortBy (fun p -> p.Number)
|> List.find (fun p -> p.Age = 21uy)

{ Number = 16\n Name = "Thiago Almada"\n Team = "Atlanta United"\n Position = Midfielder\n Age = 21uy }

Number

Name Thiago Almada

Team Atlanta United

Position

Midfielder

Age

champions2022
|> List.find (fun p -> p.Age = 18uy)

System.Collections.Generic.KeyNotFoundException: An index satisfying the predicate was not found in the collection.

   at Microsoft.FSharp.Collections.ListModule.Find[T](FSharpFunc`2 predicate, FSharpList`1 list) in D:\a\_work\1\s\src\FSharp.Core\list.fs:line 480

   at <StartupCode$FSI_0084>.$FSI_0084.main@()

   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)

   at System.Reflection.MethodInvoker.Invoke(Object obj, IntPtr* args, BindingFlags invokeAttr)

Nótese que List.find devuelve el primer elemento que encuentra. Si uno quiere todos los elementos que comparten una cierta característica, usamos List.filter

champions2022
|> List.filter (fun p -> p.Age = 21uy)

index value

{ Number = 24\n Name = "Enzo Fernández"\n Team = "Benfica"\n Position = Midfielder\n Age = 21uy }

Number

Name Enzo Fernández

Team Benfica

Position

Midfielder

Age

{ Number = 16\n Name = "Thiago Almada"\n Team = "Atlanta United"\n Position = Midfielder\n Age = 21uy }

Number

Name Thiago Almada

Team Atlanta United

Position

Midfielder

Age

champions2022
|> List.filter (fun p -> p.Age > 25uy && p.Position = Defender)

index value

{ Number = 6\n Name = "Germán Pezzella"\n Team = "Betis"\n Position = Defender\n Age = 31uy }

Number

Name Germán Pezzella

Team Betis

Position

Defender

Age

{ Number = 19\n Name = "Nicolás Otamendi"\n Team = "Benfica"\n Position = Defender\n Age = 34uy }

Number

Name Nicolás Otamendi

Team Benfica

Position

Defender

Age

{ Number = 8\n Name = "Marcos Acuña"\n Team = "Sevilla"\n Position = Defender\n Age = 31uy }

Number

Name Marcos Acuña

Team Sevilla

Position

Defender

Age

{ Number = 3\n Name = "Nicolás Tagliafico"\n Team = "Olympique de Lyon"\n Position = Defender\n Age = 30uy }

Number

Name Nicolás Tagliafico

Team Olympique de Lyon

Position

Defender

Age

let arqueros = 
    champions2022
    |> List.filter (fun p -> p.Position = GoalKeeper)

prettyPrintList arqueros    

Emiliano Martínez (30), GoalKeeper, juega en Aston Villa
Gerónimo Rulli (30), GoalKeeper, juega en Villarreal
Franco Armani (36), GoalKeeper, juega en River

Podemos usar otros métodos para procesar los datos de la lista:

champions2022
|> List.averageBy (fun p -> p.Age)

input.fsx (2,29)-(2,34) typecheck error The type 'uint8' does not support the operator 'DivideByInt'

Interesante, hay que convertir el dato a float:

champions2022
|> List.averageBy (fun p -> float p.Age)

27.76923076923077

Hay funciones que permiten procesar la lista, recolectando datos que poseen características similares.

champions2022
|> List.groupBy (fun p -> p.Team)

index value

(Aston Villa, [{ Number = 23\n  Name = "Emiliano Martínez"\n  Team = "Aston Villa"\n  Position = GoalKeeper\n  Age = 30uy }])

Item1 Aston Villa

Item2

index value

{ Number = 23\n Name = "Emiliano Martínez"\n Team = "Aston Villa"\n Position = GoalKeeper\n Age = 30uy }

Number

Name Emiliano Martínez

Team Aston Villa

Position

GoalKeeper

Age

(Villarreal, [{ Number = 12\n  Name = "Gerónimo Rulli"\n  Team = "Villarreal"\n  Position = GoalKeeper\n  Age = 30uy }; { Number = 2\n  Name = "Juan Foyth"\n  Team = "Villarreal"\n  Position = Defender\n  Age = 24uy }])

Item1 Villarreal

Item2

index value

{ Number = 12\n Name = "Gerónimo Rulli"\n Team = "Villarreal"\n Position = GoalKeeper\n Age = 30uy }

Number

Name Gerónimo Rulli

Team Villarreal

Position

GoalKeeper

Age

{ Number = 2\n Name = "Juan Foyth"\n Team = "Villarreal"\n Position = Defender\n Age = 24uy }

Number

Name Juan Foyth

Team Villarreal

Position

Defender

Age

(River, [{ Number = 1\n Name = "Franco Armani"\n Team = "River"\n Position = GoalKeeper\n Age = 36uy }])

Item1 River

Item2

index value

{ Number = 1\n Name = "Franco Armani"\n Team = "River"\n Position = GoalKeeper\n Age = 36uy }

Number

Name Franco Armani

Team River

Position

GoalKeeper

Age

(Atlético de Madrid, [{ Number = 26\n  Name = "Nahuel Molina"\n  Team = "Atlético de Madrid"\n  Position = Defender\n  Age = 24uy }; { Number = 7\n  Name = "Rodrigo De Paul"\n  Team = "Atlético de Madrid"\n  Position = Midfielder\n  Age = 28uy }])

Item1 Atlético de Madrid

Item2

index value

{ Number = 26\n Name = "Nahuel Molina"\n Team = "Atlético de Madrid"\n Position = Defender\n Age = 24uy }

Number

Name Nahuel Molina

Team Atlético de Madrid

Position

Defender

Age

{ Number = 7\n Name = "Rodrigo De Paul"\n Team = "Atlético de Madrid"\n Position = Midfielder\n Age = 28uy }

Number

Name Rodrigo De Paul

Team Atlético de Madrid

Position

Midfielder

Age

(Sevilla, [{ Number = 4\n  Name = "Gonzalo Montiel"\n  Team = "Sevilla"\n  Position = Defender\n  Age = 25uy }; { Number = 8\n  Name = "Marcos Acuña"\n  Team = "Sevilla"\n  Position = Defender\n  Age = 31uy }; { Number = 17\n  Name = "Alejandro Gómez"\n  Team = "Sevilla"\n  Position = Midfielder\n  ...

Item1 Sevilla

Item2

index value

{ Number = 4\n Name = "Gonzalo Montiel"\n Team = "Sevilla"\n Position = Defender\n Age = 25uy }

Number

Name Gonzalo Montiel

Team Sevilla

Position

Defender

Age

{ Number = 8\n Name = "Marcos Acuña"\n Team = "Sevilla"\n Position = Defender\n Age = 31uy }

Number

Name Marcos Acuña

Team Sevilla

Position

Defender

Age

{ Number = 17\n Name = "Alejandro Gómez"\n Team = "Sevilla"\n Position = Midfielder\n Age = 34uy }

Number

Name Alejandro Gómez

Team Sevilla

Position

Midfielder

Age

(Tottenham, [{ Number = 13\n Name = "Cristian Romero"\n Team = "Tottenham"\n Position = Defender\n Age = 24uy }])

Item1 Tottenham

Item2

index value

{ Number = 13\n Name = "Cristian Romero"\n Team = "Tottenham"\n Position = Defender\n Age = 24uy }

Number

Name Cristian Romero

Team Tottenham

Position

Defender

Age

(Betis, [{ Number = 6\n  Name = "Germán Pezzella"\n  Team = "Betis"\n  Position = Defender\n  Age = 31uy }; { Number = 18\n  Name = "Guido Rodríguez"\n  Team = "Betis"\n  Position = Midfielder\n  Age = 28uy }])

Item1 Betis

Item2

index value

{ Number = 6\n Name = "Germán Pezzella"\n Team = "Betis"\n Position = Defender\n Age = 31uy }

Number

Name Germán Pezzella

Team Betis

Position

Defender

Age

{ Number = 18\n Name = "Guido Rodríguez"\n Team = "Betis"\n Position = Midfielder\n Age = 28uy }

Number

Name Guido Rodríguez

Team Betis

Position

Midfielder

Age

(Benfica, [{ Number = 19\n  Name = "Nicolás Otamendi"\n  Team = "Benfica"\n  Position = Defender\n  Age = 34uy }; { Number = 24\n  Name = "Enzo Fernández"\n  Team = "Benfica"\n  Position = Midfielder\n  Age = 21uy }])

Item1 Benfica

Item2

index value

{ Number = 19\n Name = "Nicolás Otamendi"\n Team = "Benfica"\n Position = Defender\n Age = 34uy }

Number

Name Nicolás Otamendi

Team Benfica

Position

Defender

Age

{ Number = 24\n Name = "Enzo Fernández"\n Team = "Benfica"\n Position = Midfielder\n Age = 21uy }

Number

Name Enzo Fernández

Team Benfica

Position

Midfielder

Age

(Manchester United, [{ Number = 25\n  Name = "Lisandro Martínez"\n  Team = "Manchester United"\n  Position = Defender\n  Age = 24uy }])

Item1 Manchester United

Item2

index value

{ Number = 25\n Name = "Lisandro Martínez"\n Team = "Manchester United"\n Position = Defender\n Age = 24uy }

Number

Name Lisandro Martínez

Team Manchester United

Position

Defender

Age

(Olympique de Lyon, [{ Number = 3\n  Name = "Nicolás Tagliafico"\n  Team = "Olympique de Lyon"\n  Position = Defender\n  Age = 30uy }])

Item1 Olympique de Lyon

Item2

index value

{ Number = 3\n Name = "Nicolás Tagliafico"\n Team = "Olympique de Lyon"\n Position = Defender\n Age = 30uy }

Number

Name Nicolás Tagliafico

Team Olympique de Lyon

Position

Defender

Age

(Juventus, [{ Number = 5\n  Name = "Leandro Paredes"\n  Team = "Juventus"\n  Position = Midfielder\n  Age = 28uy }; { Number = 11\n  Name = "Ángel Di María"\n  Team = "Juventus"\n  Position = Forward\n  Age = 34uy }])

Item1 Juventus

Item2

index value

{ Number = 5\n Name = "Leandro Paredes"\n Team = "Juventus"\n Position = Midfielder\n Age = 28uy }

Number

Name Leandro Paredes

Team Juventus

Position

Midfielder

Age

{ Number = 11\n Name = "Ángel Di María"\n Team = "Juventus"\n Position = Forward\n Age = 34uy }

Number

Name Ángel Di María

Team Juventus

Position

Forward

Age

(Brighton, [{ Number = 20\n  Name = "Alexis Mac Allister"\n  Team = "Brighton"\n  Position = Midfielder\n  Age = 23uy }])

Item1 Brighton

Item2

index value

{ Number = 20\n Name = "Alexis Mac Allister"\n Team = "Brighton"\n Position = Midfielder\n Age = 23uy }

Number

Name Alexis Mac Allister

Team Brighton

Position

Midfielder

Age

(Bayer Leverkusen, [{ Number = 14\n  Name = "Exequiel Palacios"\n  Team = "Bayer Leverkusen"\n  Position = Midfielder\n  Age = 24uy }])

Item1 Bayer Leverkusen

Item2

index value

{ Number = 14\n Name = "Exequiel Palacios"\n Team = "Bayer Leverkusen"\n Position = Midfielder\n Age = 24uy }

Number

Name Exequiel Palacios

Team Bayer Leverkusen

Position

Midfielder

Age

(Atlanta United, [{ Number = 16\n  Name = "Thiago Almada"\n  Team = "Atlanta United"\n  Position = Midfielder\n  Age = 21uy }])

Item1 Atlanta United

Item2

index value

{ Number = 16\n Name = "Thiago Almada"\n Team = "Atlanta United"\n Position = Midfielder\n Age = 21uy }

Number

Name Thiago Almada

Team Atlanta United

Position

Midfielder

Age

(Inter, [{ Number = 22\n Name = "Lautaro Martínez"\n Team = "Inter"\n Position = Forward\n Age = 25uy }])

Item1 Inter

Item2

index value

{ Number = 22\n Name = "Lautaro Martínez"\n Team = "Inter"\n Position = Forward\n Age = 25uy }

Number

Name Lautaro Martínez

Team Inter

Position

Forward

Age

(Manchester City, [{ Number = 9\n  Name = "Julián Álvarez"\n  Team = "Manchester City"\n  Position = Forward\n  Age = 22uy }])

Item1 Manchester City

Item2

index value

{ Number = 9\n Name = "Julián Álvarez"\n Team = "Manchester City"\n Position = Forward\n Age = 22uy }

Number

Name Julián Álvarez

Team Manchester City

Position

Forward

Age

(Roma, [{ Number = 21\n Name = "Paulo Dybala"\n Team = "Roma"\n Position = Forward\n Age = 29uy }])

Item1 Roma

Item2

index value

{ Number = 21\n Name = "Paulo Dybala"\n Team = "Roma"\n Position = Forward\n Age = 29uy }

Number

Name Paulo Dybala

Team Roma

Position

Forward

Age

(Atlético Madrid, [{ Number = 15\n  Name = "Ángel Correa"\n  Team = "Atlético Madrid"\n  Position = Forward\n  Age = 27uy }])

Item1 Atlético Madrid

Item2

index value

{ Number = 15\n Name = "Ángel Correa"\n Team = "Atlético Madrid"\n Position = Forward\n Age = 27uy }

Number

Name Ángel Correa

Team Atlético Madrid

Position

Forward

Age

(París Saint-Germain, [{ Number = 10\n  Name = "Lionel Messi"\n  Team = "París Saint-Germain"\n  Position = Forward\n  Age = 35uy }])

Item1 París Saint-Germain

Item2

index value

{ Number = 10\n Name = "Lionel Messi"\n Team = "París Saint-Germain"\n Position = Forward\n Age = 35uy }

Number

Name Lionel Messi

Team París Saint-Germain

Position

Forward

Age

La función List.groupBy no devuelve una lista de jugadores, sino una lista de pares ordenados (tuplas), donde el primer elemento sería la llave común del tipo de dato recolectado, y el segundo elemento es una lista de elementos que corresponden a esa llave:

champions2022
|> List.groupBy (fun p -> p.Team)
|> List.iter (fun (team,l) -> 
                printfn "%s" team 
                prettyPrintList l
                )

Aston Villa
23: Emiliano Martínez (30), GoalKeeper, juega en Aston Villa
Villarreal
12: Gerónimo Rulli (30), GoalKeeper, juega en Villarreal
2: Juan Foyth (24), Defender, juega en Villarreal
River
1: Franco Armani (36), GoalKeeper, juega en River
Atlético de Madrid
26: Nahuel Molina (24), Defender, juega en Atlético de Madrid
7: Rodrigo De Paul (28), Midfielder, juega en Atlético de Madrid
Sevilla
4: Gonzalo Montiel (25), Defender, juega en Sevilla
8: Marcos Acuña (31), Defender, juega en Sevilla
17: Alejandro Gómez (34), Midfielder, juega en Sevilla
Tottenham
13: Cristian Romero (24), Defender, juega en Tottenham
Betis
6: Germán Pezzella (31), Defender, juega en Betis
18: Guido Rodríguez (28), Midfielder, juega en Betis
Benfica
19: Nicolás Otamendi (34), Defender, juega en Benfica
24: Enzo Fernández (21), Midfielder, juega en Benfica
Manchester United
25: Lisandro Martínez (24), Defender, juega en Manchester United
Olympique de Lyon
3: Nicolás Tagliafico (30), Defender, juega en Olympique de Lyon
Juventus
5: Leandro Paredes (28), Midfielder, juega en Juventus
11: Ángel Di María (34), Forward, juega en Juventus
Brighton
20: Alexis Mac Allister (23), Midfielder, juega en Brighton
Bayer Leverkusen
14: Exequiel Palacios (24), Midfielder, juega en Bayer Leverkusen
Atlanta United
16: Thiago Almada (21), Midfielder, juega en Atlanta United
Inter
22: Lautaro Martínez (25), Forward, juega en Inter
Manchester City
9: Julián Álvarez (22), Forward, juega en Manchester City
Roma
21: Paulo Dybala (29), Forward, juega en Roma
Atlético Madrid
15: Ángel Correa (27), Forward, juega en Atlético Madrid
París Saint-Germain
10: Lionel Messi (35), Forward, juega en París Saint-Germain

champions2022
|> List.groupBy (fun p -> p.Team)
|> List.iter (fun t -> 
                printfn "%s" (fst t)
                prettyPrintList (snd t)
                )

Aston Villa
23: Emiliano Martínez (30), GoalKeeper, juega en Aston Villa
Villarreal
12: Gerónimo Rulli (30), GoalKeeper, juega en Villarreal
2: Juan Foyth (24), Defender, juega en Villarreal
River
1: Franco Armani (36), GoalKeeper, juega en River
Atlético de Madrid
26: Nahuel Molina (24), Defender, juega en Atlético de Madrid
7: Rodrigo De Paul (28), Midfielder, juega en Atlético de Madrid
Sevilla
4: Gonzalo Montiel (25), Defender, juega en Sevilla
8: Marcos Acuña (31), Defender, juega en Sevilla
17: Alejandro Gómez (34), Midfielder, juega en Sevilla
Tottenham
13: Cristian Romero (24), Defender, juega en Tottenham
Betis
6: Germán Pezzella (31), Defender, juega en Betis
18: Guido Rodríguez (28), Midfielder, juega en Betis
Benfica
19: Nicolás Otamendi (34), Defender, juega en Benfica
24: Enzo Fernández (21), Midfielder, juega en Benfica
Manchester United
25: Lisandro Martínez (24), Defender, juega en Manchester United
Olympique de Lyon
3: Nicolás Tagliafico (30), Defender, juega en Olympique de Lyon
Juventus
5: Leandro Paredes (28), Midfielder, juega en Juventus
11: Ángel Di María (34), Forward, juega en Juventus
Brighton
20: Alexis Mac Allister (23), Midfielder, juega en Brighton
Bayer Leverkusen
14: Exequiel Palacios (24), Midfielder, juega en Bayer Leverkusen
Atlanta United
16: Thiago Almada (21), Midfielder, juega en Atlanta United
Inter
22: Lautaro Martínez (25), Forward, juega en Inter
Manchester City
9: Julián Álvarez (22), Forward, juega en Manchester City
Roma
21: Paulo Dybala (29), Forward, juega en Roma
Atlético Madrid
15: Ángel Correa (27), Forward, juega en Atlético Madrid
París Saint-Germain
10: Lionel Messi (35), Forward, juega en París Saint-Germain

Veamos cuántos jugadores aportó cada equipo:

champions2022
|> List.groupBy (fun p -> p.Team)
|> List.map (fun (t,l) -> (t, l |> List.length))

index value

(Aston Villa, 1)

Item1	Aston Villa
Item2	1

(Villarreal, 2)

Item1	Villarreal
Item2	2

(River, 1)

Item1	River
Item2	1

(Atlético de Madrid, 2)

Item1	Atlético de Madrid
Item2	2

(Sevilla, 3)

Item1	Sevilla
Item2	3

(Tottenham, 1)

Item1	Tottenham
Item2	1

(Betis, 2)

Item1	Betis
Item2	2

(Benfica, 2)

Item1	Benfica
Item2	2

(Manchester United, 1)

Item1	Manchester United
Item2	1

(Olympique de Lyon, 1)

Item1	Olympique de Lyon
Item2	1

(Juventus, 2)

Item1	Juventus
Item2	2

(Brighton, 1)

Item1	Brighton
Item2	1

(Bayer Leverkusen, 1)

Item1	Bayer Leverkusen
Item2	1

(Atlanta United, 1)

Item1	Atlanta United
Item2	1

(Inter, 1)

Item1	Inter
Item2	1

(Manchester City, 1)

Item1	Manchester City
Item2	1

(Roma, 1)

Item1	Roma
Item2	1

(Atlético Madrid, 1)

Item1	Atlético Madrid
Item2	1

(París Saint-Germain, 1)

Item1	París Saint-Germain
Item2	1

Este último procedimiento se puede resumir con List.countBy:

champions2022
|> List.countBy (fun p -> p.Team)

index value

(Aston Villa, 1)

Item1	Aston Villa
Item2	1

(Villarreal, 2)

Item1	Villarreal
Item2	2

(River, 1)

Item1	River
Item2	1

(Atlético de Madrid, 2)

Item1	Atlético de Madrid
Item2	2

(Sevilla, 3)

Item1	Sevilla
Item2	3

(Tottenham, 1)

Item1	Tottenham
Item2	1

(Betis, 2)

Item1	Betis
Item2	2

(Benfica, 2)

Item1	Benfica
Item2	2

(Manchester United, 1)

Item1	Manchester United
Item2	1

(Olympique de Lyon, 1)

Item1	Olympique de Lyon
Item2	1

(Juventus, 2)

Item1	Juventus
Item2	2

(Brighton, 1)

Item1	Brighton
Item2	1

(Bayer Leverkusen, 1)

Item1	Bayer Leverkusen
Item2	1

(Atlanta United, 1)

Item1	Atlanta United
Item2	1

(Inter, 1)

Item1	Inter
Item2	1

(Manchester City, 1)

Item1	Manchester City
Item2	1

(Roma, 1)

Item1	Roma
Item2	1

(Atlético Madrid, 1)

Item1	Atlético Madrid
Item2	1

(París Saint-Germain, 1)

Item1	París Saint-Germain
Item2	1

Se puede construir un histograma de edades:

champions2022
|> List.groupBy (fun p -> p.Age/5uy * 5uy)

index value

(30, [{ Number = 23\n  Name = "Emiliano Martínez"\n  Team = "Aston Villa"\n  Position = GoalKeeper\n  Age = 30uy }; { Number = 12\n  Name = "Gerónimo Rulli"\n  Team = "Villarreal"\n  Position = GoalKeeper\n  Age = 30uy }; { Number = 6\n  Name = "Germán Pezzella"\n  Team = "Betis"\n  Position = Defen...

Item1

Item2

index value

{ Number = 23\n Name = "Emiliano Martínez"\n Team = "Aston Villa"\n Position = GoalKeeper\n Age = 30uy }

Number

Name Emiliano Martínez

Team Aston Villa

Position

GoalKeeper

Age

{ Number = 12\n Name = "Gerónimo Rulli"\n Team = "Villarreal"\n Position = GoalKeeper\n Age = 30uy }

Number

Name Gerónimo Rulli

Team Villarreal

Position

GoalKeeper

Age

{ Number = 6\n Name = "Germán Pezzella"\n Team = "Betis"\n Position = Defender\n Age = 31uy }

Number

Name Germán Pezzella

Team Betis

Position

Defender

Age

{ Number = 19\n Name = "Nicolás Otamendi"\n Team = "Benfica"\n Position = Defender\n Age = 34uy }

Number

Name Nicolás Otamendi

Team Benfica

Position

Defender

Age

{ Number = 8\n Name = "Marcos Acuña"\n Team = "Sevilla"\n Position = Defender\n Age = 31uy }

Number

Name Marcos Acuña

Team Sevilla

Position

Defender

Age

{ Number = 3\n Name = "Nicolás Tagliafico"\n Team = "Olympique de Lyon"\n Position = Defender\n Age = 30uy }

Number

Name Nicolás Tagliafico

Team Olympique de Lyon

Position

Defender

Age

{ Number = 17\n Name = "Alejandro Gómez"\n Team = "Sevilla"\n Position = Midfielder\n Age = 34uy }

Number

Name Alejandro Gómez

Team Sevilla

Position

Midfielder

Age

{ Number = 11\n Name = "Ángel Di María"\n Team = "Juventus"\n Position = Forward\n Age = 34uy }

Number

Name Ángel Di María

Team Juventus

Position

Forward

Age

(35, [{ Number = 1\n  Name = "Franco Armani"\n  Team = "River"\n  Position = GoalKeeper\n  Age = 36uy }; { Number = 10\n  Name = "Lionel Messi"\n  Team = "París Saint-Germain"\n  Position = Forward\n  Age = 35uy }])

Item1

Item2

index value

{ Number = 1\n Name = "Franco Armani"\n Team = "River"\n Position = GoalKeeper\n Age = 36uy }

Number

Name Franco Armani

Team River

Position

GoalKeeper

Age

{ Number = 10\n Name = "Lionel Messi"\n Team = "París Saint-Germain"\n Position = Forward\n Age = 35uy }

Number

Name Lionel Messi

Team París Saint-Germain

Position

Forward

Age

(20, [{ Number = 26\n  Name = "Nahuel Molina"\n  Team = "Atlético de Madrid"\n  Position = Defender\n  Age = 24uy }; { Number = 13\n  Name = "Cristian Romero"\n  Team = "Tottenham"\n  Position = Defender\n  Age = 24uy }; { Number = 25\n  Name = "Lisandro Martínez"\n  Team = "Manchester United"\n  Po...

Item1

Item2

index value

{ Number = 26\n Name = "Nahuel Molina"\n Team = "Atlético de Madrid"\n Position = Defender\n Age = 24uy }

Number

Name Nahuel Molina

Team Atlético de Madrid

Position

Defender

Age

{ Number = 13\n Name = "Cristian Romero"\n Team = "Tottenham"\n Position = Defender\n Age = 24uy }

Number

Name Cristian Romero

Team Tottenham

Position

Defender

Age

{ Number = 25\n Name = "Lisandro Martínez"\n Team = "Manchester United"\n Position = Defender\n Age = 24uy }

Number

Name Lisandro Martínez

Team Manchester United

Position

Defender

Age

{ Number = 2\n Name = "Juan Foyth"\n Team = "Villarreal"\n Position = Defender\n Age = 24uy }

Number

Name Juan Foyth

Team Villarreal

Position

Defender

Age

{ Number = 20\n Name = "Alexis Mac Allister"\n Team = "Brighton"\n Position = Midfielder\n Age = 23uy }

Number

Name Alexis Mac Allister

Team Brighton

Position

Midfielder

Age

{ Number = 24\n Name = "Enzo Fernández"\n Team = "Benfica"\n Position = Midfielder\n Age = 21uy }

Number

Name Enzo Fernández

Team Benfica

Position

Midfielder

Age

{ Number = 14\n Name = "Exequiel Palacios"\n Team = "Bayer Leverkusen"\n Position = Midfielder\n Age = 24uy }

Number

Name Exequiel Palacios

Team Bayer Leverkusen

Position

Midfielder

Age

{ Number = 16\n Name = "Thiago Almada"\n Team = "Atlanta United"\n Position = Midfielder\n Age = 21uy }

Number

Name Thiago Almada

Team Atlanta United

Position

Midfielder

Age

{ Number = 9\n Name = "Julián Álvarez"\n Team = "Manchester City"\n Position = Forward\n Age = 22uy }

Number

Name Julián Álvarez

Team Manchester City

Position

Forward

Age

(25, [{ Number = 4\n  Name = "Gonzalo Montiel"\n  Team = "Sevilla"\n  Position = Defender\n  Age = 25uy }; { Number = 7\n  Name = "Rodrigo De Paul"\n  Team = "Atlético de Madrid"\n  Position = Midfielder\n  Age = 28uy }; { Number = 5\n  Name = "Leandro Paredes"\n  Team = "Juventus"\n  Position = Mid...

Item1

Item2

index value

{ Number = 4\n Name = "Gonzalo Montiel"\n Team = "Sevilla"\n Position = Defender\n Age = 25uy }

Number

Name Gonzalo Montiel

Team Sevilla

Position

Defender

Age

{ Number = 7\n Name = "Rodrigo De Paul"\n Team = "Atlético de Madrid"\n Position = Midfielder\n Age = 28uy }

Number

Name Rodrigo De Paul

Team Atlético de Madrid

Position

Midfielder

Age

{ Number = 5\n Name = "Leandro Paredes"\n Team = "Juventus"\n Position = Midfielder\n Age = 28uy }

Number

Name Leandro Paredes

Team Juventus

Position

Midfielder

Age

{ Number = 18\n Name = "Guido Rodríguez"\n Team = "Betis"\n Position = Midfielder\n Age = 28uy }

Number

Name Guido Rodríguez

Team Betis

Position

Midfielder

Age

{ Number = 22\n Name = "Lautaro Martínez"\n Team = "Inter"\n Position = Forward\n Age = 25uy }

Number

Name Lautaro Martínez

Team Inter

Position

Forward

Age

{ Number = 21\n Name = "Paulo Dybala"\n Team = "Roma"\n Position = Forward\n Age = 29uy }

Number

Name Paulo Dybala

Team Roma

Position

Forward

Age

{ Number = 15\n Name = "Ángel Correa"\n Team = "Atlético Madrid"\n Position = Forward\n Age = 27uy }

Number

Name Ángel Correa

Team Atlético Madrid

Position

Forward

Age

champions2022
|> List.groupBy (fun p -> p.Age/5uy * 5uy)
|> List.map (fun (t,l) -> (t, l.Length))
|> List.sort 

index value

(20, 9)

Item1	20
Item2	9

(25, 7)

Item1	25
Item2	7

(30, 8)

Item1	30
Item2	8

(35, 2)

Item1	35
Item2	2

La función List.partition nos permite agrupar los elementos en dos listas con características disjuntas:

champions2022
|> List.map (fun p -> (p.Name,p.Age))
|> List.partition (fun (name,age) -> age < 30uy)

([(Nahuel Molina, 24); (Gonzalo Montiel, 25); (Cristian Romero, 24); ... ], [(Emiliano Martínez, 30); (Gerónimo Rulli, 30); (Franco Armani, 36); ... ])

Item1

index value

(Nahuel Molina, 24)

Item1	Nahuel Molina
Item2	24

(Gonzalo Montiel, 25)

Item1	Gonzalo Montiel
Item2	25

(Cristian Romero, 24)

Item1	Cristian Romero
Item2	24

(Lisandro Martínez, 24)

Item1	Lisandro Martínez
Item2	24

(Juan Foyth, 24)

Item1	Juan Foyth
Item2	24

(Rodrigo De Paul, 28)

Item1	Rodrigo De Paul
Item2	28

(Leandro Paredes, 28)

Item1	Leandro Paredes
Item2	28

(Alexis Mac Allister, 23)

Item1	Alexis Mac Allister
Item2	23

(Guido Rodríguez, 28)

Item1	Guido Rodríguez
Item2	28

(Enzo Fernández, 21)

Item1	Enzo Fernández
Item2	21

(Exequiel Palacios, 24)

Item1	Exequiel Palacios
Item2	24

(Thiago Almada, 21)

Item1	Thiago Almada
Item2	21

(Lautaro Martínez, 25)

Item1	Lautaro Martínez
Item2	25

(Julián Álvarez, 22)

Item1	Julián Álvarez
Item2	22

(Paulo Dybala, 29)

Item1	Paulo Dybala
Item2	29

(Ángel Correa, 27)

Item1	Ángel Correa
Item2	27

Item2

index value

(Emiliano Martínez, 30)

Item1	Emiliano Martínez
Item2	30

(Gerónimo Rulli, 30)

Item1	Gerónimo Rulli
Item2	30

(Franco Armani, 36)

Item1	Franco Armani
Item2	36

(Germán Pezzella, 31)

Item1	Germán Pezzella
Item2	31

(Nicolás Otamendi, 34)

Item1	Nicolás Otamendi
Item2	34

(Marcos Acuña, 31)

Item1	Marcos Acuña
Item2	31

(Nicolás Tagliafico, 30)

Item1	Nicolás Tagliafico
Item2	30

(Alejandro Gómez, 34)

Item1	Alejandro Gómez
Item2	34

(Ángel Di María, 34)

Item1	Ángel Di María
Item2	34

(Lionel Messi, 35)

Item1	Lionel Messi
Item2	35

let menoresde30, mayoresde30 = 
    champions2022
    |> List.map (fun p -> (p.Name,p.Age))
    |> List.partition (fun (name,age) -> age < 30uy)

printfn $"Los menores de 30 son {menoresde30.Length}"
printfn $"Los mayores de 30 son {mayoresde30.Length}"

Los menores de 30 son 16
Los mayores de 30 son 10

Finalmente, algunas funciones nos permiten evaluar una determinada característica de una lista:

champions2022
|> List.forall (fun p -> p.Age < 30uy)

False

menoresde30
|> List.forall (fun (_,a) -> a < 30uy)

False

List.findIndex

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