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  1. def int_to_roman(input):
  2.    """
  3.    Convert an integer to Roman numerals.
  4.  
  5.    Examples:
  6.    >>> int_to_roman(0)
  7.    Traceback (most recent call last):
  8.    ValueError: Argument must be between 1 and 3999
  9.  
  10.    >>> int_to_roman(-1)
  11.    Traceback (most recent call last):
  12.    ValueError: Argument must be between 1 and 3999
  13.  
  14.    >>> int_to_roman(1.5)
  15.    Traceback (most recent call last):
  16.    TypeError: expected integer, got <type 'float'>
  17.  
  18.    >>> for i in range(1, 21): print int_to_roman(i)
  19.    ...
  20.    I
  21.    II
  22.    III
  23.    IV
  24.    V
  25.    VI
  26.    VII
  27.    VIII
  28.    IX
  29.    X
  30.    XI
  31.    XII
  32.    XIII
  33.    XIV
  34.    XV
  35.    XVI
  36.    XVII
  37.    XVIII
  38.    XIX
  39.    XX
  40.    >>> print int_to_roman(2000)
  41.    MM
  42.    >>> print int_to_roman(1999)
  43.    MCMXCIX
  44.    """
  45.    if type(input) != type(1):
  46.       raise TypeError, "expected integer, got %s" % type(input)
  47.    if not 0 < input < 4000:
  48.       raise ValueError, "Argument must be between 1 and 3999"   
  49.    ints = (1000, 900,  500, 400, 100,  90, 50,  40, 10,  9,   5,  4,   1)
  50.    nums = ('M',  'CM', 'D', 'CD','C', 'XC','L','XL','X','IX','V','IV','I')
  51.    result = ""
  52.    for i in range(len(ints)):
  53.       count = int(input / ints[i])
  54.       result += nums[i] * count
  55.       input -= ints[i] * count
  56.    return result
  57.  
  58.  
  59.  
  60. def roman_to_int(input):
  61.    """
  62.    Convert a roman numeral to an integer.
  63.  
  64.    >>> r = range(1, 4000)
  65.    >>> nums = [int_to_roman(i) for i in r]
  66.    >>> ints = [roman_to_int(n) for n in nums]
  67.    >>> print r == ints
  68.    1
  69.  
  70.    >>> roman_to_int('VVVIV')
  71.    Traceback (most recent call last):
  72.     ...
  73.    ValueError: input is not a valid roman numeral: VVVIV
  74.    >>> roman_to_int(1)
  75.    Traceback (most recent call last):
  76.     ...
  77.    TypeError: expected string, got <type 'int'>
  78.    >>> roman_to_int('a')
  79.    Traceback (most recent call last):
  80.     ...
  81.    ValueError: input is not a valid roman numeral: A
  82.    >>> roman_to_int('IL')
  83.    Traceback (most recent call last):
  84.     ...
  85.    ValueError: input is not a valid roman numeral: IL
  86.    """
  87.    if type(input) != type(""):
  88.       raise TypeError, "expected string, got %s" % type(input)
  89.    input = input.upper()
  90.    nums = ['M', 'D', 'C', 'L', 'X', 'V', 'I']
  91.    ints = [1000, 500, 100, 50,  10,  5,   1]
  92.    places = []
  93.    for c in input:
  94.       if not c in nums:
  95.          raise ValueError, "input is not a valid roman numeral: %s" % input
  96.    for i in range(len(input)):
  97.       c = input[i]
  98.       value = ints[nums.index(c)]
  99.       # If the next place holds a larger number, this value is negative.
  100.       try:
  101.          nextvalue = ints[nums.index(input[i +1])]
  102.          if nextvalue > value:
  103.             value *= -1
  104.       except IndexError:
  105.          # there is no next place.
  106.          pass
  107.       places.append(value)
  108.    sum = 0
  109.    for n in places: sum += n
  110.    # Easiest test for validity...
  111.    if int_to_roman(sum) == input:
  112.       return sum
  113.    else:
  114.       raise ValueError, 'input is not a valid roman numeral: %s' % input
Success #stdin #stdout 0.01s 7200KB
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https://ideone.com/4pAWRD
language:
Python (cpython 2.7.16)
created:
14 days ago
visibility:
public

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