recursion

cesar.hs

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+import Data.Char
+
+lowers :: String -> Int
+lowers xs = length [x | x <- xs, x >= 'a' && x <= 'z']
+
+count :: Char -> String ->Int
+count x xs = length [x' | x' <- xs, x==x']
+
+positions :: Eq a => a -> [a] -> [Int]
+positions x xs = [i | (x',i) <- zip xs [0..n], x == x']
+  where n = length xs - 1
+
+let2int :: Char -> Int
+let2int c = ord c - ord 'a' --caracteres a unicode
+
+int2let :: Int -> Char
+int2let n = chr (ord 'a' + n)
+
+shift :: Int -> Char -> Char
+shift n c | isLower c = int2let ((let2int c + n) `mod` 26)
+          | otherwise = c
+
+cifrar :: Int -> String -> String
+cifrar n xs = [shift n x | x <- xs]
+
+table :: [Float]
+table = [11.72,1.49, 3.87, 4.67,13.72,0.69,1.00,1.18,5.28,0.52,0.11,5.24,3.08,6.83,8.44,2.89,1.11,6.41,7.20,4.60,4.55,1.05,0.04,0.14,1.09,0.47]
+
+porciento :: Int -> Int -> Float --fromIntegral :: Int a Float
+porciento n m = (fromIntegral n / fromIntegral m) * 100
+
+frec :: String -> [Float]
+frec xs = [porciento (count x xs) n | x <- ['a'..'z']]
+  where n = lowers xs 
+
+chisqr :: [Float] -> [Float] -> Float
+chisqr os es = sum [((o-e)^2)/e | (o,e) <- zip os es]
+
+rotate :: Int -> [a] -> [a]
+rotate n xs = drop n xs ++ take n xs
+
+crack :: String -> String
+crack xs = cifrar (-factor) xs
+  where
+    factor = head (positions (minimum chitab) chitab)
+    chitab = [chisqr (rotate n table') table | n <- [0..25]]
+    table' = frec xs

recursion.hs

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+import Data.Set as Set
+doRep x n | n <= 0 = []
+          | otherwise = x:doRep x (n-1)
+
+miLista = [1,4,8,2,3,3,5,1,6]
+miConj = Set.fromList(miLista)
+

recursion.py

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+def doRep(x, n):
+    y = []
+    if n==0:
+        return []
+    else:
+        y = doRep(x,n-1)
+        print(y)
+        y.append(x)
+        return y
+
+def lSum(list):
+    if not list:
+        return 0
+    else:
+        return list[0]+lSum(list[1:])
+
+lSum2 = lambda list: 0 if not list \
+    else list[0] + lSum2(list[1:])
+
+miLista = [1,4,8,2,3,3,5,1,6]
+miConj = set(miLista)

tarea2.tex

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+\documentclass[10pt,a4paper]{article}
+\usepackage[spanish]{babel}
+\usepackage[utf8]{inputenc}
+\usepackage{amsmath}
+\usepackage{hyperref}
+\usepackage{amsfonts}
+\usepackage{amssymb}
+%\usepackage{braket}
+\author{Programación funcional para la física computacional}
+\title{Tarea 2}
+\begin{document}
+\maketitle
+
+\begin{enumerate}
+\item Define la magnitud de la fuierza gravitacional como una función \emph{curriada}
+  \begin{equation*}
+    |\vec{F}|= -G\frac{M\cdot m}{r^2}
+  \end{equation*}
+  
+  (puede ser en python o Haskell, donde prefieras) y úsala para calcular la fuerza que ejerce la Tierra sobre ti (puedes dar un aproximado de tu peso), la Luna y sobre Neptuno (usa como constantes lo que no vayta a cambiar y sólo da como argumentos lo que si cambie para estos casos.).
+\item En Haskell define el operador producto punto y cálcula el área formada entre los vectores $(1,2,3)$ y $(2,3,1)$. Puedes definir los vectores como listas.
+\item De un eexperimento del laboratorio de mecánica te dan la si
+\end{enumerate}
+
+\end{document}