Problem Description

Complete the solution so that it splits the string into pairs of two characters.
If the string contains an odd number of characters then it should replace the missing
second character of the final pair with an underscore ('_').

Examples:

'abc' => ['ab', 'c_']
'abcdef' => ['ab', 'cd', 'ef']

Note

Keywords:

• count: gets length of string
• odd?: checks if number is odd
• str: concatenates strings (adds underscore if needed)
• *partition: splits collection into groups of specified size
• map: applies function to each element
• apply str: joins characters in each pair back into strings
• ->>: threading macro for cleaner data transformation

Implementation

; implement
(defn solution [s]
  (let [padded-string (if (odd? (count s))
                        (str s "_")
                        s)]
    (->> padded-string
         (partition 2)
         (map #(apply str %)))))
         ; test
; execute implement function
(defn tester [arg exp]
  (= (solution arg) exp))

; args & exception
(comment
  (tester "abc" ["ab" "c_"])
  (tester "abcdef" ["ab" "cd" "ef"])
  (tester "" [])
  (tester "x" ["x_"])
  (tester "Banana" ["Ba" "na" "na"])
  (tester "CodeWars" ["Co" "de" "Wa" "rs"]))