Syntax

Question 1

How to sum two values?

Answer 1

(+ 2 2)

; 4

Question 2

How to thread something and return nil when some function returns nil?

Answer 2

(some-> …)

Question 3

How to declare a function for test something?

Answer 3

(deftest test-something
(testing “describe the test”
…))

Question 4

How to require a namespace and use functions without the prefix?

Answer 4

Using :require [… :refer :all]

Question 5

What is uberjar?

Answer 5

Create a stand-alone .jar to be executed.

Question 6

How to execute a .jar file?

Answer 6

java -jar /path/to/file.jar

Question 7

How to start REPL with lein?

Answer 7

lein repl

Question 8

What are the main control flow in clojure?

Answer 8

if, do, when

Question 9

The best way to get a value of a map with keyword?

Answer 9

(:name person)

Question 10

What are de diference between list an vectores?

Answer 10

When you add something to the list it goes to the front, instead of going to the end in vectors.

Question 11

What are the main advantage to use a set?

Answer 11

Sets store unique values, if you try to add a value that already exists, it will be ignored.

Question 12

What is high order functions?

Answer 12

Functions that returns or receive a function

Question 13

How to declare a function with multiple-arity?

Answer 13

(defn x-chop
  ([name chop-type]
     (str "I " chop-type " chop " name "! Take that!"))
  ([name]
     (x-chop name "karate")))

Question 14

How to get the rest of arguments received in a function?

Answer 14

(defn favorite-things
[name & things]
(str “Hi, “ name “, here are my favorite things: “
(clojure.string/join “, “ things)))

(favorite-things “Doreen” “gum” “shoes” “kara-te”)
; => “Hi, Doreen, here are my favorite things: gum, shoes, kara-te”

Question 15

How to destructure a vector passed as argument?

Answer 15

;; Return the first element of a collection
(defn my-first
[[first-thing]] ; Notice that first-thing is within a vector
first-thing)

(my-first [“oven” “bike” “war-axe”])
; => “oven”

Question 16

How to destructure a map and mainten the orginal value?

Answer 16

(defn receive-treasure-location
[{:keys [lat lng] :as treasure-location}]
(println (str “Treasure lat: “ lat))
(println (str “Treasure lng: “ lng))

;; One would assume that this would put in new coordinates for your ship
(steer-ship! treasure-location))

Question 17

How to declare anonymous functions?

Answer 17

(fn [x] (+ x 1))
#(+ % 1)

Question 18

What is closure?

Answer 18

Functions that returns another functions.