Functional Programming?

Question 1: Increment all the numbers in the vector [4 7 9 10] by one. Use the map function. Hint: the function inc.

(map (fn [x] (inc x)) [4 7 9 10])

# or using the shorter form to define an anonymous function:
(map |(inc $) [4 7 9 10])

# or simply:
(map inc [4 7 9 10])

Question 2: Do the same as in the previous exercise, but leave only the even results in the vector. Use the functions filter and even?

(filter even? (map inc [4 7 9 10]))

Question 3: Use the for structure to go through this vector of maps and return a sequence of the :values, aka this [10.3 20.06 30.1]

[{:id 1 :value 10.3} {:id 2 :value 20.06} {:id 7 :value 30.1}]

(def data [{:id 1 :value 10.3} {:id 2 :value 20.06} {:id 7 :value 30.1}])
(for [m :in data]
  (m :value))

Question 4: Use the function update-in to change 3 into 4 in the value below:

{:shops [:shop-1]
         :customers [{:id "Bob"
                      :account {:balance 3}}]}

(def data {:shops [:shop-1]
           :customers [{:id "Bob"
                        :account {:balance 3}}]})
(update-in data [:customers 0 :account :balance] inc)

Question 5: Create a function that combine a vector of maps like this:

(combine [{:a 1 :b 2} {:c 3} {:d 4 :e 5}])
==> {:a 1 :b 2 :c 3 :d 4 :e 5}

(defn combine [maps]
  (apply merge maps))