更新

Python-100-Days/Day01-15/Day09/rational.py

@@ -0,0 +1,76 @@
+"""
+
+运算符重载 - 自定义分数类
+
+Version: 0.1
+Author: 骆昊
+Date: 2018-03-12
+
+"""
+
+from math import gcd
+
+
+class Rational(object):
+
+	def __init__(self, num, den=1):
+		if den == 0:
+			raise ValueError('分母不能为0')
+		self._num = num
+		self._den = den
+		self.normalize()
+
+	def simplify(self):
+		x = abs(self._num)
+		y = abs(self._den)
+		factor = gcd(x, y)
+		if factor > 1:
+			self._num //= factor
+			self._den //= factor
+		return self
+
+	def normalize(self):
+		if self._den < 0:
+			self._den = -self._den
+			self._num = -self._num
+		return self
+
+	def __add__(self, other):
+		new_num = self._num * other._den + other._num * self._den
+		new_den = self._den * other._den
+		return Rational(new_num, new_den).simplify().normalize()
+
+	def __sub__(self, other):
+		new_num = self._num * other._den - other._num * self._den
+		new_den = self._den * other._den
+		return Rational(new_num, new_den).simplify().normalize()
+
+	def __mul__(self, other):
+		new_num = self._num * other._num
+		new_den = self._den * other._den
+		return Rational(new_num, new_den).simplify().normalize()
+
+	def __truediv__(self, other):
+		new_num = self._num * other._den
+		new_den = self._den * other._num
+		return Rational(new_num, new_den).simplify().normalize()
+
+	def __str__(self):
+		if self._num == 0:
+			return '0'
+		elif self._den == 1:
+			return str(self._num)
+		else:
+			return '(%d/%d)' % (self._num, self._den)
+
+
+if __name__ == '__main__':
+	r1 = Rational(2, 3)
+	print(r1)
+	r2 = Rational(6, -8)
+	print(r2)
+	print(r2.simplify())
+	print('%s + %s = %s' % (r1, r2, r1 + r2))
+	print('%s - %s = %s' % (r1, r2, r1 - r2))
+	print('%s * %s = %s' % (r1, r2, r1 * r2))
+	print('%s / %s = %s' % (r1, r2, r1 / r2))