なんか想像以上に手こずったよ^ ^;
case式内が見苦しい..
もっと簡単なやり方あるんだろうな。Integer#dollarizeを定義してみた。
数字を英語のドル表記に変換。
#!/usr/bin/env ruby class Integer def dollarize num_set = split_by_unit.map(&:__dollarize__) join_with_unit(num_set) end def split_by_unit(unit=10**3) q, r = divmod(unit) if q < unit [q, r] else q.split_by_unit(unit) << r end end UNDER_TENS = Hash[[*0..9].zip %w(Zero One Two Three Four Five Six Seven Eight Nine)] TEENS = Hash[[*10..19].zip %w(Ten Eleven Twelve Thirteen Fourteen Fifteen Sixteen Seventeen Eighteen Nineteen)] TYS = Hash[[*20.step(90,10)].zip %w(Twenty Thirty Forty Fifty Sixty Seventy Eighty Ninety)] DIGITS = Hash[[10,100,1000].zip %w(Ten Hundred Thousand)] def __dollarize__ ten_flag = false digitaize.map do |n, digit| case when n.zero? && !ten_flag # do_nothing when digit == 10 unless n == 1 TYS[n*digit] else ten_flag = true nil end when digit == 1 && ten_flag ten_flag = false TEENS[10+n] else "#{UNDER_TENS[n]}#{DIGITS[digit]}" end end.join end def digitaize ns = split_by_unit(10) ns.map.with_index { |n, i| [n, 10**(ns.size-1-i)] } end private def join_with_unit(num_set, seps = %w(Thousand Million)) return UNDER_TENS[0] if num_set == ['',''] num_set.reverse.inject do |mem, var| sep = seps.shift sep = nil if var.empty? [var, mem].join(sep) end end end puts ARGF.map { |line| line.to_i.dollarize + 'Dollars' }
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