迭代Clojure向量

Question

I am implementing a Clojure function (gol [coll]) that receives a vector of vectors of the same size with 1 and 0, iterates it checking the near positions of each index and returns a new board; something like Conway's Game of Life

Input:

`(gol [[0 0 0 0 0]
       [0 0 0 0 0]
       [0 1 1 1 0]
       [0 0 0 0 0]
       [0 0 0 0 0]])`

Output:

`[[0 0 0 0 0]
  [0 0 1 0 0]
  [0 0 1 0 0]
  [0 0 1 0 0]
  [0 0 0 0 0]]`

How can I iterate the vectors and change the values at the same time?

Answer 1

Use assoc-in :

(assoc-in v [0 0] 1)

The above will set the top left value to 1 .

To set many at once you can reduce over assoc-in .

(def new-values [[[0 0] 1] 
                 [[0 1] 2] 
                 [[0 2] 3]])

(reduce
  (fn [acc ele]
    (apply assoc-in acc ele))
  v
  new-values)

;;=> [[1 2 3 0 0] ...]

To go from your input to your output the transform would be:

[[[2 1] 0]
 [[2 3] 0]
 [[1 2] 1]
 [[3 2] 1]]