English is a peculiar language. english_number() takes an integer, and returns the long, written form most famously used on checks and the like. Algorithm inspired by some old HP online docs.
to_19 = ( 'zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten', 'eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen' ) tens = ( 'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety') denom = ( '', 'thousand', 'million', 'billion', 'trillion', 'quadrillion', 'quintillion', 'sextillion', 'septillion', 'octillion', 'nonillion', 'decillion', 'undecillion', 'duodecillion', 'tredecillion', 'quattuordecillion', 'sexdecillion', 'septendecillion', 'octodecillion', 'novemdecillion', 'vigintillion' ) # convert a value < 100 to English. def _convert_nn(val): if val < 20: return to_19[val] for (dcap, dval) in ((k, 20 + (10 * v)) for (v, k) in enumerate(tens)): if dval + 10 > val: if val % 10: return dcap + '-' + to_19[val % 10] return dcap # convert a value < 1000 to english, special cased because it is the level that kicks # off the < 100 special case. The rest are more general. This also allows you to # get strings in the form of 'forty-five hundred' if called directly. def _convert_nnn(val): word = '' (mod, rem) = (val % 100, val // 100) if rem > 0: word = to_19[rem] + ' hundred' if mod > 0: word = word + ' ' if mod > 0: word = word + _convert_nn(mod) return word def english_number(val): if val < 100: return _convert_nn(val) if val < 1000: return _convert_nnn(val) for (didx, dval) in ((v - 1, 1000 ** v) for v in range(len(denom))): if dval > val: mod = 1000 ** didx l = val // mod r = val - (l * mod) ret = _convert_nnn(l) + ' ' + denom[didx] if r > 0: ret = ret + ', ' + english_number(r) return ret
