Ruby multidimensional array

Question

Maybe it\'s just my lack of abilities to find stuff here that is the problem, but I can\'t find anything about how to create multidimensional arrays in Ruby.

Could s

Answer 1

There are two ways to initialize multi array (size of 2). All the another answers show examples with a default value.

Declare each of sub-array (you can do it in a runtime):

multi = []
multi[0] = []
multi[1] = []

or declare size of a parent array when initializing:

multi = Array.new(2) { Array.new }

Usage example:

multi[0][0] = 'a'
multi[0][1] = 'b'
multi[1][0] = 'c'
multi[1][1] = 'd'

p multi # [["a", "b"], ["c", "d"]]
p multi[1][0] # "c"

So you can wrap the first way and use it like this:

@multi = []
def multi(x, y, value)
  @multi[x] ||= []
  @multi[x][y] = value
end

multi(0, 0, 'a')
multi(0, 1, 'b')
multi(1, 0, 'c')
multi(1, 1, 'd')

p @multi # [["a", "b"], ["c", "d"]]
p @multi[1][0] # "c"