CODEWITHSUNDEEP
clojure
user10185182
user10185182

Reputation: 33

Simple 2D array in Clojure

I'm still learning Clojure and can't seem to find a simple answer for this. I've seen similar questions answered with complex code specific for the OP's issue so please let me know the most accurate or acceptable version of the following:

int[][] arrayTest = new int[width][height];
...
for (int x = 0; x < width; x++) {
  for (int y = 0; y < height; y++) {
    int a = arrayTest[x][y];
    if (a < 100) {
      arrayTest[x][y] = 0;
    }
  }
}

Upvotes: 3

Views: 1895

Answers (2)

status203
status203

Reputation: 876

Represented as a sequence of sequences...

user=> (doc repeat)
-------------------------
clojure.core/repeat
([x] [n x])
  Returns a lazy (infinite!, or length n if supplied) sequence of xs.
nil

user=> (def width 8)
#'user/width
user=> (def height 6)
#'user/height

user=> (repeat width 0)
(0 0 0 0 0 0 0 0)

user=> (pprint (repeat height (repeat width 0)))
((0 0 0 0 0 0 0 0)
 (0 0 0 0 0 0 0 0)
 (0 0 0 0 0 0 0 0)
 (0 0 0 0 0 0 0 0)
 (0 0 0 0 0 0 0 0)
 (0 0 0 0 0 0 0 0))
nil

Upvotes: 0

Aleph Aleph
Aleph Aleph

Reputation: 5395

The literal translation is straightforward:

(def array-test
  (make-array Integer/TYPE width height))

(doseq [x (range width)
        y (range height)]
  (when (< (aget array-test x y) 100)
    (aset-int array-test x y 0)))

Note, however, that arrays are not commonly used in Clojure. Unless you want to do fast computations or work with existing Java code, you shouldn't normally be creating arrays and other mutable data structures. Most likely, what you want to implement can be done with Clojure's persistent collections instead.

Upvotes: 7

Related Questions