Pretty prints a 2D array with or without a header

formatted_table.rb

require 'colorize'

def print_table(table, with_header = true)
  # Calculate widths
  widths = []
  table.each do |line|
    line.each_with_index do |col, c|
      widths[c] = (widths[c] && widths[c] > col.length) ? widths[c] : col.length
    end
  end
  # Indent the last column left.
  last = widths.pop()
  format = widths.collect { |n| "%-#{n}s" }.join("  |   ".black) + "  #{'|'.black}  %-#{last}s\n"
  table.each_with_index do |line, i|
    if i == 0 && with_header
      printf(format.black, *line)
    else
      printf(format, *line)
    end
  end
end

Given a two-dimensional array, print_table pretty prints a table that looks a bit like this: