Enjoy !

So now with the exercises :

1. Pretty standard problem - find all prime numbers up to a number given in the argument.

2. Function that takes a function (two numbers as arguments) and a list of numbers and returns a list of those two argument functions but already applied to numbers in the list given. That way we gain a list of functions taking one number.

3. Find all automorphic numbers up to a given number.

4. Rewrite the following functions so they use (.) operator :

one = sum ( takeWhile (<10000) (filter isPrime [1..]) ) two = map (\x -> cos (sqrt x))

Solutions:

1.

allPrime :: (Integral a) => a -> [a] allPrime range = filter isPrime [2..range] isPrime :: (Integral a) => a -> Bool isPrime x = not (isNotPrime 1 x) isNotPrime :: (Integral a) => a -> a -> Bool isNotPrime dv nr | dv == nr = False | dv == 1 = False || isNotPrime 2 nr | otherwise = nr `mod` dv==0 || isNotPrime (dv+1) nr2.

partialL ::( Num a ) => (a-> a -> b) -> [a] -> [ a->b ] partialL _ [] = [] partialL f (x:xs) = f x : partialL f xsUsage :

let bla = partialL (\x -> \y -> x+y) [1,2,3,4] map ($ 2) bla [3,4,5,6]

3.

automorphic :: Int -> [Int] automorphic y = [ x | x <- (take y [1..]), show x == (splitter x) ] splitter :: (Num a) => a -> [Char] splitter x = snd ( splitAt ( length (show sq) - length (show x) ) (show sq) ) where sq = x^2

4.

one = sum . takeWhile (<10000) . filter isPrime [1..] two = map (cos . sqrt)

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