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def format_roman(case, counter):
    ones = ['i', 'x', 'c', 'm']
    fives = ['v', 'l', 'd']
    label, index = '', 0
    # This will die of IndexError when counter is too big
    while counter > 0:
        counter, x = divmod(counter, 10)
        if x == 9:
            label = ones[index] + ones[index+1] + label
        elif x == 4:
            label = ones[index] + fives[index] + label
        else:
            if x >= 5:
                s = fives[index]
                x = x-5
            else:
                s = ''
            s = s + ones[index]*x
            label = s + label
        index = index + 1
    if case == 'I':
        return label.upper()
    return label

for i in xrange(20):
    print format_roman("I", i)

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def format_roman(counter, upper_case=True):
    ...
    return label.upper() if upper_case else label

Code: Alles auswählen

def format_roman(counter, upper_case=True):
    ones = ['I', 'X', 'C', 'M']
    fives = ['V', 'L', 'D']
    ...
    return label if upper_case else label.lower()

Code: Alles auswählen

# -*- coding: iso-8859-15 -*-

"""This module converts Roman numerals
into integers and also reversed.
The numbers must be in range 1...4999!

Methods:
 rtoi    - Roman number -> Integer
 itor    - Integer -> Roman number

Example:
>>> rtoi('XVI')
<<< 16
>>> itor(16)
<<< 'XVI'"""

import re

class OutOfRangeError(Exception): pass
class NotIntegerError(Exception): pass
class InvalidRomanNumeralError(Exception): pass

MAX_ROMAN_NUMERAL = 4999

RomanNumeralMap = (('M', 1000), ('CM', 900), ('D', 500),
                   ('CD', 400), ('C', 100), ('XC', 90),
                   ('L', 50), ('XL', 40), ('X', 10),
                   ('IX', 9), ('V', 5), ('IV', 4),
                   ('I',  1))

ValidRomanNumeralPattern = re.compile( \
 """
 ^
 M{0,4}            # thousands - 0 to 4 M's
 (CM|CD|D?C{0,3})  # hundreds - 900 (CM), 400 (CD), 0-300 (0 to 3 C's),
                   # or 500-800 (D, followed by 0 to 3 C's)
 (XC|XL|L?X{0,3})  # tens - 90 (XC), 40 (XL), 0-30 (0 to 3 X's),
                   # or 50-80 (L, followed by 0 to 3 X's)
 (IX|IV|V?I{0,3})  # ones - 9 (IX), 4 (IV), 0-3 (0 to 3 I's),
                   # or 5-8 (V, followed by 0 to 3 I's)
 $
 """, re.VERBOSE)

def itor(n):
  """itor(int) -> string
     Converts integers to Roman numbers"""

  if not (0 < n < 5000):
    raise OutOfRangeError, "number out of range (must be 1...%s)" \
                           % MAX_ROMAN_NUMERAL
  if int(n) <> n:
    raise NotIntegerError, "non-integers can not be converted"
  result = ""
  for num, i in RomanNumeralMap:
    while n >= i:
      result += num
      n -= i
  return result

def rtoi(s):
  """rtoi(string) -> int
     Converts Roman numbers to integers"""

  if not s:
    raise InvalidRomanNumeralError, "Input can not be blank"
  if not ValidRomanNumeralPattern.search(s):
    raise InvalidRomanNumeralError, "Invalid Roman numeral: '%s'" % s

  result = 0
  index = 0
  for num, i in RomanNumeralMap:
    while s[index:index+len(num)] == num:
      result += i
      index += len(num)
  return result