qoelet

facebook {
    id = "some_id"
    secret = "some_secret"
}   

qoelet

import Data.Configurator
import qualified Data.Configurator as C

main :: IO ()
main = do
    -- other code
    cfg <- C.load [C.Required "../.settings.cfg"]
    app_id <- C.lookup cfg "facebook.id" :: IO (Maybe String)
    app_secret <- C.lookup cfg "facebook.secret" :: IO (Maybe String)
    let base_url = "https://graph.facebook.com/oauth/access_token?"

qoelet

-- Specifying lag = n

diff :: (Num a) => [a] -> Int -> [a]
diff [] n = []
diff (x:xs) n | length (xs) > n = (xs!!n - x) : diff xs n
              | otherwise = []

qoelet

-- the diff() function from R

diff :: (Num a) => [a] -> [a]
diff [] = []
diff (_:[]) = []
diff (x:y:xs) = (y - x) : diff (y:xs)

qoelet

-- Simple plpython function performing a full text search
CREATE OR REPLACE FUNCTION fts(sterm text) RETURNS SETOF text
AS $$
    sterms = plpy.quote_literal(sterm)
    words = " & ".join(sterms.split(" "))
    res = plpy.execute("SELECT title FROM articles WHERE to_tsvector('english',title || ' ' ||  abstract) @@ to_tsquery('english', %s)" % words)
    return [ (r["title"]) for r in res]
$$ LANGUAGE plpythonu;

-- dummy database of NYTimes articles (via their API)

qoelet

require(fArma)

# assumes data is already a ts object
i = diff(data)
z = data[1]
m = mean(i)
n = length(data)
k = 3

fit = armaFit(~ arma(1,1), data=i)

qoelet

-- Collatz conjecture

collatz :: Integer -> [Integer]
collatz 1 = [1]
collatz n | even n = n : collatz (n `div` 2)
          | otherwise = n : collatz ((3 * n) + 1)

qoelet

-- prime factorization
-- definitely needs improvement :X
 
getPrimeFactor :: Integer -> [Integer] -> (Integer, Integer)
getPrimeFactor n (p:ps) | n `mod` p == 0 = (p, (n `div` p))
                        | otherwise = getPrimeFactor n ps
 
getPrimeFactors :: Integer -> [Integer] -> [Integer]
getPrimeFactors n s | not (result == 1) = factor : getPrimeFactors result s
                    | otherwise = [factor]

qoelet

destruct :: Integer -> [Integer]
destruct 0 = []
destruct x = destruct (x `div` 10) ++ [(x `mod` 10)]

construct :: [Integer] -> Integer
construct [] = 0
construct (x:xs) = (x * (10 ^ (length xs))) + construct xs

-- *Main> construct (destruct 123456)
-- 123456

qoelet

-- Calculating a Fibonacci number (see: http://en.wikipedia.org/wiki/Fibonacci_number)
fib :: Integer -> Integer
fib 0 = 0
fib 1 = 1
fib n = fib (n - 1) + fib (n - 2)

-- Solving a quiz, I needed to generate a Fibonacci sequence up to a certain limit, e.g. fib n < limit
-- Usual recursion here is expensive and inefficient, takes too long.
fibLst :: Integer -> [Integer]
fibLst 0 = []