diegopacheco

  map (+1) [1, 2, 3, 4, 5]           -- [2,3,4,5,6]

  map succ [1, 2, 3, 4, 5]           -- [2,3,4,5,6]

  filter (>3) [1,5,3,2,1,6,4,3,2,1]  -- [5,6,4]

diegopacheco

-- hof.hs
apply2 :: (a -> a) -> a -> a  
apply2 f x = f (f x)

-- 
-- ghci hof.hs 
--
apply2 (*2) 100   -- 400

diegopacheco

 map (\x -> x * 2) [1..4]   -- [2,4,6,8]

diegopacheco

def add(n:Int)(a:Int) = n + a

val add2 = add(2)(_)

add(5)(5)  // 10 

add2(30)  //  32

diegopacheco

def benchmark(msg:String)(f:()=>Unit) = {
   val init = System.currentTimeMillis
   f
   val end = System.currentTimeMillis()
   println(msg + " in: " + (end - init) + " ms")
 }

benchmark("for benchmark ")( () => 
    for(i <- 1 to 1000){
      println(i)

diegopacheco

   max 10 20     -- 20
  
  (max 10) 20    -- 20

diegopacheco

-- currying.hs
mul2 :: (Num a) => a -> a -> a
mul2 x y = x * y

--
-- ghci currying.hs
--
mul2 2 3  -- 6

let double = mul2 2

diegopacheco

map (\x -> x + 3) [1,6,3,2]  -- [4,9,6,5]

map (\(a,b) -> a + b) [(1,2),(3,5),(6,3),(2,6),(2,5)] -- [3,8,9,8,7]   

-- add.hs
addThree :: (Num a) => a -> a -> a -> a
addThree = \x -> \y -> \z -> x + y + z

--
-- ghci add.hs

diegopacheco

() => 2 +2       // () => Int = <function0>

(() => 2 + 2)()  // 4

List(1,2,3,4,5).map( i => i + 1 )  // List(2, 3, 4, 5, 6)

List(1,2,3,4,5,6,7,8,9,10).filter( n => n >= 7  )   // List(7, 8, 9, 10)

List(1,2,3,4,5,6,7,8,9,10).filter( _  >= 7  )       // List(7, 8, 9, 10)

diegopacheco

 cd /
 mkdir /home/diegopacheco
 echo "export HOME=/home/diegopacheco" >>.bashrc
 echo "export HOME=/home/diegopacheco" >>.bash_profile
 cp .bashrc .bash_profile /home/diegopacheco
 echo "cd" >>.bashrc