Haskell for Todos 2

 

Algunos ejercicios hechos en Haskell.

Haskell

Haskell es un lenguaje de programación estandarizado puramente funcional con semántica no estricta, llamado así por el lógico Haskell Curry. Es uno de los lenguajes funcionales más populares y el lenguaje funcional perezoso en el que se está realizando la mayor parte de la investigación.

Programando con Haskell

Extensión: *.hs y *.lhs

Compilar

$ ghc holamundo.hs

Ejecutar

$ ./holamundo

Abrir el REPL

Cargar script

$ ghci
> 12 + 45
> [1,2,3,4,5]
> let x = [3,9,6]
> :cd RUTA_DEL_SCRIPT
> :l script.hs
> :! clear
> :q

Operaciones básicas

$ ghci
> rem 120 100
> 12 + 54
> "Hola, mundo mundial del mundo universal"
> not True
> not False
> True || True
> False || True
> True && True
> False && True
> not (True || True)
> not (9/=3)
> 8/=6
> let nombre ="Juan Ortiz"
> nombre
> "Juan Pablo"/=nombre
> "Dan "++"Kerr"
> nombre++" Alvarez"
> let lista = [1,2,3]
> length lista
> head lista
> tail lista
> let cierto = if 7>3 then "X" else "Y"
> cierto
> :! clear
> :! pwd
> :! ls
> :q

Comentarios

--Este es un simple comentario en Haskell

Comentarios multilínea

{-
  Este es
     un comentario
   multi línea en
   Haskell
-}

sumar.hs

add :: Integer -> Integer -> Integer
add x y = x+y
{-
 $ ghci
 > :cd RUTA_DEL_SCRIPT
 > :l sumar.hs
 > sumar 4 5 --9
 > sumar 6 2 --8
-}

Síntaxis básica para crear una función

-- definimos función
nombreFunc :: Tipo -> Tipo ->Tipo
nombreFunc x 0 = x
nombreFunc 0 y = y
nombreFunc x y = x - y

Estructuras selectivas

if 2 > 0
	then "Verdadero: 2 es mayor a cero"
	else "Falso: 2 es menor a cero"

let decide = if 2 > 0 then "Verdadero: 2 es mayor a cero" else "Falso: 2 es menor a cero"

Sitio oficial:

• https://www.haskell.org/
• http://gettingsharper.de/tag/haskell/
• http://learnyouahaskell.com/
• http://rosettacode.org/wiki/Category:Haskell
• https://hoogle.haskell.org/?hoogle=getLine
• https://wiki.haskell.org/Tutorials/Programming_Haskell/Argument_handling
• http://www.willamette.edu/~fruehr/haskell/evolution.html
• http://book.realworldhaskell.org/
• Haskell por el bien de todos
• Learning Haskell

view raw README.md hosted with ❤ by GitHub

	import System.Environment
	main = do
	args <- getArgs
	putStrLn "Los argumentos son:"
	mapM_ putStrLn args

view raw argumentos.hs hosted with ❤ by GitHub

	import System.Environment
	main = do
	args <- getArgs
	file <- if null args
	then do putStr "Archivo: " ; getLine
	else pure (head args)
	putStr "Procesando..."
	putStrLn file
	writeFile file "Hoy es 25 de abril de 2021"
	{-
	$ ghc argumentos_print.hs
	$ ./argumentos_print archivo.dat
	-}

view raw argumentos_print.hs hosted with ❤ by GitHub

	main = do
	let sueldo=9000
	let edo_civil="soltero"
	putStrLn("Sueldo inicial: "++show sueldo)
	--funciones
	--let aumento sueldo = (0.25*sueldo) + sueldo
	--let bono sueldo = sueldo + 900
	--let total b s = b + s
	--putStrLn("Aumento: "++show(aumento(sueldo)))
	--putStrLn("Bono: "++show(bono(sueldo)))
	if sueldo < 10000
	then
	do
	let aumento sueldo = (0.25*sueldo) + sueldo
	--let bono sueldo = sueldo + 900
	--putStrLn("Bono: "++show(bono(sueldo)))
	putStrLn("Aumento: "++show(aumento(sueldo)))
	--let total bono aumento = bono + aumento
	--putStrLn("Sueldo final: "++show(total(bono,aumento)))
	else
	putStrLn "El sueldo es mayor o igual a 10000. No recibe aumento."
	if edo_civil == "casado"
	then
	do
	let bono sueldo = sueldo + 900
	putStrLn("Bono: "++show(bono(sueldo)))
	else
	putStrLn "El empleado es casado. No recibe bono."

view raw aumento.hs hosted with ❤ by GitHub

	{-
	No. combinatorio
	-}
	fact :: Int -> Int
	fact 0 = 1
	fact n = fact(n-1)*n
	combinatorio :: Int -> Int -> Int
	combinatorio x 0 = 0
	combinatorio 0 y = 0
	combinatorio x y = fact(x) `div` fact(x)*fact(x-y)
	-- Uso:
	{-
	$ ghci
	> :cd RUTA_SCRIPT
	> :l combinatorio.hs
	> combinatorio 10 3
	-}

view raw combinatorio.hs hosted with ❤ by GitHub

	{-
	Esto es un comentario multilinea en Haskell
	[1,2,3] == [1,2,3] = True
	[1,2] == [1,2,3] = False
	[] == [1,2] = False
	[1,2,3] == [] = False
	-}
	{-
	*Main> comp_listas [1] []
	False
	*Main> comp_listas [1] [1]
	True
	*Main> comp_listas [1,2] [2,1]
	False
	*Main> comp_listas [] [2,1]
	False
	*Main> comp_listas [] [1]
	False
	*Main> comp_listas [32] [30+2]
	True
	-}
	comp_listas :: [Int] -> [Int] -> Bool
	comp_listas [] [] = True
	comp_listas [] _ = False
	comp_listas _ [] = False
	comp_listas (a:b) (c:d) | (a == c) = comp_listas b d
	| otherwise = False

view raw comparar.hs hosted with ❤ by GitHub

	cubo :: Int -> Int
	cubo num = num * num * num

view raw cubo.hs hosted with ❤ by GitHub

	cuentaCifras lista = [if num<10 then "Una cifra" else "Dos cifras"
	| num <- lista
	, odd num]

view raw cuentaCifras.hs hosted with ❤ by GitHub

	decide :: Int -> String
	decide x = if x > 0
	then "Verdadero: "++ show x ++" es mayor a cero"
	else "Falso: "++show x++" es igual a cero"

view raw decide.hs hosted with ❤ by GitHub

	divisible x y = if (x `mod` y) == 0
	then "son divisibles"
	else "no son divisibles"

view raw divisible.hs hosted with ❤ by GitHub

	doubleSmall x = if x > 100
	then x
	else x*2

view raw doubleSmall.hs hosted with ❤ by GitHub

	$ ghci
	> :?
	> :! pwd
	> :cd /home/user/Documentos/scripts
	> :! cat funcion.hs
	> :l programa.hs
	> programa variable
	> :! clear
	> :! ls
	> :edit programa.hs
	> :list

view raw ejecutar.txt hosted with ❤ by GitHub

	esMayor x y = if x > y
	then show x ++" es mayor"
	else show y ++" es mayor"

view raw esMayor.hs hosted with ❤ by GitHub

	euler :: Double -> Double
	euler 0.0 = 1.0
	euler n = 1.0 / product [1..n] + euler (n - 1.0)

view raw euler.hs hosted with ❤ by GitHub

	factorial 0 = 1
	factorial n = factorial(n-1)*n

view raw factorial.hs hosted with ❤ by GitHub

	fibonacci 0 = 0
	fibonacci 1 = 1
	fibonacci n = fibonacci(n-1) + fibonacci(n-2)

view raw fibonacci.hs hosted with ❤ by GitHub

	func :: (Int, Int) -> (Int, Int) -> (Int, Int)
	func (a, b) (c, d) = (a+c, b+d)

view raw funcion.hs hosted with ❤ by GitHub

	sumaCinco :: Int -> Int
	sumaCinco x = x+5
	multiplicaPorTres :: Int -> Int
	multiplicaPorTres x = x*3
	funcionDeAltoOrden f g x = f(g(x))
	{-
	$ ghci
	> :cd RUTA_SCRIPT
	> :l funciones.hs
	> funcionDeAltoOrden multiplicaPorTres sumaCinco 6
	33
	-}

view raw funciones.hs hosted with ❤ by GitHub

	{-
	Fundamentos en Haskell
	1. Entrar al shell (repl)
	$ ghci
	> :cd /home/fernando/Documentos/pruebasHaskell
	> :l
	> :q -- Salir del shell
	-}
	{-
	5.
	-}
	{-
	4. Creando tipos
	-}
	type Entero = Int
	triple :: Entero -> Entero
	triple 0 = 0
	triple n = n * 3
	{-
	nombreFunc :: Tipo -> Tipo -> Tipo
	nombreFunc a b = a + b
	En lenguajes como Javascript sería:
	function nombreFunc(a, b){
	return a + b;
	}
	o
	var nombreFunc = (a, b) => a+b;
	-}
	{-
	RESULT=0
	X=0
	Y=1
	IF X==0 THEN
	RESULT = Y
	END IF
	IF Y==0 THEN
	RESULT = X
	END IF
	IF X!=0 AND Y!=0 THEN
	RESULT = X+Y
	END IF
	3. Crear funcion con dos parametros(x,y). Si x es 0, el resultado es y. Si y es 0, el resultado es x. Si ambos son distintos de 0, e resultado es la suma de x+y.
	-}
	nombreFunc :: Int -> Int -> Int
	nombreFunc x 0 = x
	nombreFunc 0 y = y
	nombreFunc x y = x+y
	{-
	2. Función que devuelva 1 si el valor de entrada es 0
	Ej.
	factorial 0 = 1
	factorial n = factorial(n-1)*n
	En Javascript sería:
	function factorial(num){
	if(num <= 0){
	return 1;
	}else{
	return factorial(num-1)*num;
	}
	}
	let valor = factorial(0); // 1
	valor = factorial(5);// 120
	$ ghci
	> :cd RUTA_SCRIPT
	> :l fundamentos.hs
	> verifica 0 -- 1
	> verifica 2 -- 4
	-}
	verifica :: Int -> Int
	verifica 0 = 1
	verifica n = n*2
	{-
	-- 1. funciones
	$ ghci
	> :cd RUTA_SCRIPT
	> :l fundamentos.hs
	> sumaFunc 4 3
	> restaFunc 4 5
	> suma = sumaFunc 5 4
	> suma
	> resta = restaFunc 10 5
	> resta
	> operaFunc suma resta
	-}
	sumaFunc :: Int -> Int -> Int
	sumaFunc x y = x+y
	restaFunc :: Int -> Int -> Int
	restaFunc x y = x-y
	operaFunc :: Int -> Int -> Int
	operaFunc x y = x*y

view raw fundamentos.hs hosted with ❤ by GitHub

	guarda x | (x == 0) = 0
	| (x == 1) = 1
	| otherwise = 10

view raw guarda.hs hosted with ❤ by GitHub

	hola :: IO()
	hola = putStrLn "Hola, mundo en Haskell!!"

view raw hola.hs hosted with ❤ by GitHub

	module Main where
	main :: IO()
	main = do
	putStrLn "Hola, mundo en Haskell!!"
	-- $ ghc holamonde.hs
	-- $ ./holamonde

view raw holamonde.hs hosted with ❤ by GitHub

	--Compilar: ghc holamundo.hs
	--Ejecutar: ./holamundo
	main = putStrLn "Bienvenido al mundo Haskell!"

view raw holamundo.hs hosted with ❤ by GitHub

	siEsMayor m n = if m > n
	then show m ++ " es mayor"
	else show n ++ " es mayor"
	{-
	$ ghci
	> :cd RUTA_SCRIPT
	> :l if.hs
	> siEsMayor 12 3
	> siEsMayor 3 44
	> :q
	-}
	{-
	if 2 > 0
	then "Verdadero: 2 es mayor a cero"
	else "Falso: 2 es menor a cero"
	-}

view raw if.hs hosted with ❤ by GitHub

	--Obtener la longitud de una lista
	longitud lista = sum[ 1 | x <-lista]
	{-
	$ ghci
	> :cd RUTA_DEL_SCRIPT
	> :l longitud.hs
	> let lista = [1..30]
	> longitud lista
	> :q
	-}

view raw longitud.hs hosted with ❤ by GitHub

	mcd::Int->Int->Int
	mcd x 0 = x
	mcd x y = mcd y (mod x y)
	{-
	$ ghci
	> :cd RUTA_SCRIPT
	> :l maximocomundiv.hs
	> mcd 3 4
	> mcd 5 6
	> :q
	-}

view raw maximocomundiv.hs hosted with ❤ by GitHub

	my_and :: Bool -> Bool -> Bool
	my_and False _ = False
	my_and _ False = False
	my_and True True = True

view raw my_and.hs hosted with ❤ by GitHub

	nombres :: (String, String, String)
	nombres = ("Fernando","Uriel", "Alma")
	select_prim (x, _, _) = x
	select_seg (_, y, _) = y
	select_ter (_, _, z) = z

view raw nombres.hs hosted with ❤ by GitHub

	type Nombre = String
	type Edad = Int
	type Idioma = String
	type Persona = (Nombre, Edad, Idioma)
	persona::Persona
	persona = ("Horacio", 1994, "Portugues")
	primero :: Persona -> Nombre
	primero (n, e, i) = n
	segundo :: Persona -> Edad
	segundo (n, e, i) = e
	tercero :: Persona -> Idioma
	tercero (n, e, i) = i

view raw persona.hs hosted with ❤ by GitHub

	primes = filterPrime [2..]
	where filterPrime (p:xs) =
	p : filterPrime [x | x <- xs, x `mod` p /= 0]

view raw primos.hs hosted with ❤ by GitHub

	promedio :: Float -> Float -> Float
	promedio a b = (a+b)/2.0
	{-
	$ ghci
	> :cd RUTA_SCRIPT
	> :l promedio.hs
	> promedio 9 4
	> 33.08 `promedio` 11.5 `promedio` 12.1
	-}

view raw promedio.hs hosted with ❤ by GitHub

	restar :: Int -> Int -> Int
	restar 0 y = y
	restar x 0 = x
	restar x y = x - y
	{-
	$ ghci
	> :cd /home/user/Documentos/pruebasHaskell
	> :l restar.hs
	> restar 3 2
	> restar 10 5
	-}

view raw restar.hs hosted with ❤ by GitHub

restoDeDosNum m n = m `mod` n

view raw restoDeDosNum.hs hosted with ❤ by GitHub

	--author: Fer Carraro
	main = do
	putStrLn "Introduce tu nombre:"
	nombre <- getLine
	putStrLn("Hola, "++nombre)
	--Esto es un comentario

view raw saludar.hs hosted with ❤ by GitHub

	suma 1 = 1
	suma n = suma(n-1) + n

view raw suma.hs hosted with ❤ by GitHub

	suma :: Int -> Int -> Int
	suma x y = x + y
	{-
	$ ghci
	> :cd RUTA_SCRIPTS
	> :l suma1.hs
	> suma 3 4
	> suma 8 3
	-}

view raw suma1.hs hosted with ❤ by GitHub

sumaDiez x = x + 10

view raw sumaDiez.hs hosted with ❤ by GitHub

	sumando :: Integer -> Integer -> Integer
	sumando x y = x+y
	{-
	$ ghci
	> :cd RUTA_DEL_SCRIPT
	> :l sumando.hs
	> sumando
	-}

view raw sumando.hs hosted with ❤ by GitHub

sumaNumeros x y = x + y

view raw sumaNumeros.hs hosted with ❤ by GitHub

	sumaTres num = num + num + num
	{-
	$ ghci
	> :cd RUTA_DEL_SCRIPT
	> :l sumaTres
	> sumaTres 9 --27
	> sumaTres 88 --264
	> :q
	-}

view raw sumaTres.hs hosted with ❤ by GitHub

	--listas
	size_list [] = 0
	size_list (x:xs) = 1 + size_list xs

view raw tam.hs hosted with ❤ by GitHub

	verdadero :: Bool -> Bool -> Bool
	verdadero x y = x && y

view raw verdadero.hs hosted with ❤ by GitHub

	vocales frase = [ letra | letra <- frase,
	letra `elem` ['a','e','i','o','u'] ]
	{-
	$ ghci
	> :cd RUTA_DEL_SCRIPT
	> :l vocales.hs
	> let frase = "europa renacida"
	> vocales frase
	> :q
	-}

view raw vocales.hs hosted with ❤ by GitHub

Enlaces: https://emanuelpeg.blogspot.com/search?q=haskell https://alquimistadecodigo.blogspot.com/search?q=haskell http://learn.hfm.io/