Sum of arrays of different size [closed]

Answer 1

a = [[45, 96, 0, 96, 96, 96, 0],
     [ 4, 55, 6, 55,  4,  4, 2, 55]]

Array.new(a.max_by(&:size).size) { |i| a.reduce(0) { |t,e| t+e[i].to_i } }
  #=>[49, 151, 6, 151, 100, 100, 2, 55]

Note that nil.to_i #=> 0 (ref).

Another example:

a = [[1], [2,3,4], [5,6]]

Array.new(a.max_by(&:size).size) { |i| a.reduce(0) { |t,e| t+e[i].to_i } }
  #=> [8,9,4]