Python implementation of Roman Numerals

gonzalo123/Python/RomanNumerals.py

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+class RomanNumerals:
+    _numerals = {
+            1 : "I",
+            4 : "IV",  # substract
+            5 : "V",
+            9: "IX", # substract
+            10 : "X",
+            40 : "XL", # substract
+            50 : "L",
+            90 : "XC", # substract
+            100 : "C",
+            400 : "CD", # substract
+            500 : "D",
+            900 : "CM", # substract
+            1000 : "M"
+            }
+
+    def _getKeys(self):
+        keys = self._numerals.keys() 
+        keys.sort() 
+        keys.reverse()
+
+        return keys
+
+    def num2Romans(self, number):
+        out = ""
+        for i in self._getKeys():
+            count = number / i
+            out = "%s%s" % (out, self._numerals[i] * count)
+            number -= i * count
+        return out
+
+    def roman2Nums(self, roman):
+        romanValues = ('M', 'D', 'C', 'L', 'X', 'V', 'I')
+        romanKeys = (1000, 500, 100, 50, 10, 5, 1)
+
+        out = 0
+
+        for i in range(len(roman)):
+            c = roman[i]
+            value = romanKeys[romanValues.index(c)]
+            if len(roman) > i+1:
+                nextvalue = romanKeys[romanValues.index(roman[i+1])]
+                if nextvalue > value:
+                    value *= -1
+            out += value
+
+        return out

gonzalo123/Python/RomanNumeralsTest.py

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+import unittest
+import RomanNumerals
+
+class RomanNumeralsTest (unittest.TestCase):
+    def setUp(self):
+        self.rn = RomanNumerals.RomanNumerals()
+
+    def _test_simple(self):
+        self.assertEquals("I", self.rn.num2Romans(1))
+        self.assertEquals(1, self.rn.roman2Nums(""))
+
+        self.assertEquals("V", self.rn.num2Romans(5))
+        self.assertEquals5(5, self.rn.roman2Nums("V"))
+
+        self.assertEquals("X", self.rn.num2Romans(10))
+        self.assertEquals(10, self.rn.roman2Nums(""))
+
+    def test_complex(self):
+        self.assertEquals("VII", self.rn.num2Romans(7))
+        self.assertEquals(7, self.rn.roman2Nums("VII"))
+
+        self.assertEquals("XIV", self.rn.num2Romans(14))
+        self.assertEquals(14, self.rn.roman2Nums("XIV"))
+
+        self.assertEquals("XXIII", self.rn.num2Romans(23))
+        self.assertEquals(23, self.rn.roman2Nums("XXIII"))
+
+        self.assertEquals("CXLV", self.rn.num2Romans(145))
+        self.assertEquals(145, self.rn.roman2Nums("CXLV"))
+
+        self.assertEquals("MCMLXXV", self.rn.num2Romans(1975))
+        self.assertEquals(1975, self.rn.roman2Nums("MCMLXXV"))
+
+        self.assertEquals("XLII", self.rn.num2Romans(42))
+        self.assertEquals(42, self.rn.roman2Nums("XLII"))
+
+    def test_kata(self):
+        self.assertEquals("MCMXCIX", self.rn.num2Romans(1999))
+        self.assertEquals(1999, self.rn.roman2Nums("MCMXCIX"))
+
+
+if __name__ == '__main__':
+    unittest.main()