Readable matrix printing

matrix_readable.rb

require 'matrix'

module ReadableArrays
    def readable(factor: 1, method: :rjust)
        repr = to_a.map { |row|
            row.map(&:inspect)
        }
        
        column_widths = repr.transpose.map { |col|
            col.map(&:size).max + factor
        }
        
        res = ""
        repr.each { |row|
            row.each_with_index { |el, j|
                res += el.send method, column_widths[j]
            }
            res += "\n"
        }
        res.chomp
    end
end

class Matrix
    include ReadableArrays
end
class Array
    include ReadableArrays
end

arr = [[1, 20, 3], [20, 3, 19], [-32, 3, 5]]
mat = Matrix[*arr]

p arr
#=> [[1, 20, 3], [20, 3, 19], [-2, 3, 5]]
p mat
#=> Matrix[[1, 20, 3], [20, 3, 19], [-2, 3, 5]]

puts arr.readable
#=>
#    1 20  3
#   20  3 19
#  -32  3  5
puts mat.readable
#=>
#    1 20  3
#   20  3 19
#  -32  3  5
puts mat.readable(method: :ljust)
#=>
# 1   20 3
# 20  3  19
# -32 3  5
puts mat.readable(method: :center)
#=>
#  1  20  3
#  20  3 19
# -32  3  5