2次元配列で表現した行列で列ごとの合計値を算出したい 2 [ [1,2,3], [4,5,6] ..... [n-2,n-1,n] ] [(1+4+...+n-2), (2+5+...+n-1), (3+6+...+n)] `ruby` def aaa(arr) if arr.size == 1 arr elsif arr.size == 2 bbb(arr[0],arr[1]) else bbb(arr[0], aaa(arr[1..-1])) end end def bbb(arr1,arr2) ret = Array.new(arr1.size, 0) arr1.size.times{|n| ret[n] += arr1[n] + arr2[n]} ret end a = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]] aaa(a) => [22, 26, 30]

a = [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]]
a.transpose.map { |n| n.inject(:+) }
# => [22, 26, 30]