Clojure Koans Walkthrough

1. Introduction
2. Lists
3. Vectors
4. Sets
5. Maps
6. Functions
7. Conditionals
8. Higher Order Functions
9. Runtime Polymorphism
10. Lazy Sequences
11. Sequence Comprehensions
12. Creating Functions
13. Recursion
14. Destructuring
15. Refs
16. Atoms
17. Macros
18. Datatypes
19. Java Interop
20. Partition

Recommended Books

• ← Lists
• Sets →

3. Vectors - Koans Walkthrough

This video serves covers a key data structure in Clojure: vectors. Clojure is unique among many Lisps, in that it has a first-class syntax for representing vectors (using square brackets).

Here is the 03_vectors.clj source code:

(meditations
  "You can use vectors in clojure to create an 'Array' like structure"
  (= __ (count [42]))

  "You can create a vector in several ways"
  (= __ (vec nil))

  "And populate it in either of these ways"
  (= __ (vec '(1)))

  "There is another way as well"
  (= __ (vector nil))

  "But you can populate it with any number of elements at once"
  (= [1 __] (vec '(1 2)))

  "And add to it as well"
  (= __ (conj (vec nil) 333))

  "You can get the first element of a vector like so"
  (= __ (first [:peanut :butter :and :jelly]))

  "And the last in a similar fashion"
  (= __ (last [:peanut :butter :and :jelly]))

  "Or any index if you wish"
  (= __ (nth [:peanut :butter :and :jelly] 3))

  "You can also slice a vector"
  (= __ (subvec [:peanut :butter :and :jelly] 1 3))

  "Equality with collections is in terms of values"
  (= (list 1 2 3) (vector 1 2 __)))