RaymondWies

;; Word Count
(ns word-count)

(defn word-count [string]
  (let [remove-punc (fn [s] (clojure.string/replace s #"\W" ""))]
    (-> string (clojure.string/lower-case) (clojure.string/split #" ")
      (#(map remove-punc %)) (#(remove empty? %)) (frequencies))))

;; RNA Transcription
(ns rna-transcription)

RaymondWies

;; zuzukin's solution to A nil key
;; https://4clojure.com/problem/134

(fn [k dict]
  (if (contains? dict k)
    (nil? (dict k))
    false))
    
;; zuzukin's solution to Map Defaults
;; https://4clojure.com/problem/156

RaymondWies

{- Replacer function via recursion. Replaces old element x with new element e at specified index in a list. -}
replace :: Int -> a -> [a] -> [a]
replace _ _ []     = []
replace 0 e (x:xs) = e : xs
replace i e (x:xs) = x : replace (i-1) e xs

{- Swapper function via concatenation. Takes element in a list at initial index i and returns new list at desired index j. -}
swap :: Int -> Int -> [a] -> [a]
swap _ _ [] = []
swap i j xs | i == j || i >= length xs || j >= length xs = xs

RaymondWies

nthPrime :: Integral a => Int -> a
nthPrime = (!!) listOfPrimes . pred

listOfPrimes :: Integral a => [a]
listOfPrimes = 2:3:5:7:filter testPrime [9,11..]

testPrime :: Integral a => a -> Bool
testPrime 2 = True
testPrime x | x < 2 || even x = False
            | otherwise = all (\i -> mod x i /= 0) [3,5..floor.sqrt.fromIntegral $ x]

RaymondWies

{- Project Euler Problem 1:
   Find the sum of all natural numbers below z that are factors of x or y -}
sumFactors :: Integral a => a -> a -> a -> a
sumFactors x y z = sum $ filter (\n -> mod n x == 0 || mod n y == 0) [1.. pred z]

{- Project Euler Problem 2:
   Find the sum of all even Fibonacci numbers below upper value lim -}
sumList :: Integral a => a -> a
sumList = sum . fiboEvenLazyList
    where fibo n               = if n < 4 then n else fibo (n - 1) + fibo (n - 2)

RaymondWies

from math import sqrt

def set_div(n):
#screens for 0, 1, 2, and screens out all other evens greater than 2
#then passes a maximum odd divisor up to sqrt(number) to test_prime(div)
    if n == 2:  return True
    elif n < 2 or not n % 2:  return False
    else:  return test_prime(int(sqrt(n))) if int(sqrt(n)) % 2 else test_prime(int(sqrt(n))-1)

def test_prime(div):

RaymondWies

'''Each function below is an independent test for prime number given any number n that returns True or False.
The code is designed to be used as a test function in your code, like within filter(test_prime, [list of integers]) 
or within list comprehension prime_list = [num for num in nums if test_prime(num)].

Each test function assumes positive integers so validate inputs with abs(), int(), etc. separately.'''

from math import sqrt

def test_prime(n):
#probabilistic test for prime with no false negatives (all real primes return True)

RaymondWies

'''x = r * x * (1 - x) expressed as a Python function four different ways.  
x is a population fraction as a rounded float, where each x is a successive 
iteration or base case (initial population fraction).  r is rate of growth.  
gen is generation, where gen = 0 is initial state with x = x0 and gen = 20 is 20th 
generation with x being population after 20 iterations of the above formula.

Call each function below as new_pop(gen, x=?, r=?) or simply as new_pop(gen) with
default values for initial x and r set at 0.02 and 2.7 as per example in Gleick's book.'''