How to count the number of arrays in a nested array

Question

I want to count the number of arrays in the nested arrays of an array

array = [[["-", 0, "I"], ["+", 0, "you"]], [["+", 3, "i"]], [["-", 4, "loved"], ["-", 5, "that"], ["+", 5, "it"], ["+", 6, "tasted"], ["+", 7, "like"]]]

This example would have 8 nested arrays inside the arrays in the array array. (not sure if I worded that right)

Answer 1

The easiest/cleanest way is to partially flatten an array by one nesting level:

array.flatten(1).count

Other option is to sum sub-arrays:

array.inject([], :+).count

However the real question you need to ask to yourself is - how did I end up with such a weird construct?

Answer 2

The key here is to properly state the question - I assume it to be count the number of arrays inside the nested array, which themselves do not contain another arrays.

def count_inner_arrays(arr)
  sub_arrays = arr.select { |el| el.is_a? Array }
  sub_arrays.empty? ? 1 : sub_arrays.map(&method(:count_inner_arrays)).inject(0, :+)
end