python - 添加分数类 python

Question

我有一个类的这一部分，它接受一个整数和一个分数并将它们加在一起。

def __add__(self, g):
       whole_add=self.whole_number + g.whole_number
       numerator = (self.fraction.numerator * g.fraction.denominator ) + (g.fraction.numerator * self.fraction.denominator)
       denominator = self.fraction.denominator * g.fraction.denominator
       f=Fraction(numerator,denominator)
       return '{} and {}'.format(whole_add,f)

fraction_1 = Fraction(3, 4)
fraction_2 = Fraction(2, 3)
mixed_num_1 = MixedNumber(2, fraction_1)
mixed_num_2 = MixedNumber(1, fraction_2)
print(mixed_num_1 + mixed_num_2)

结果是 3 和 17/12，当它应该是 4 和 5/12 时，我不确定该怎么做，我假设如果分数 >= 1。任何帮助都会很大赞赏

Answer 1

如果您使用 fractions library ，您可以对所有内容求和，然后取分数的 int() 部分:

def __add__(self, g):
    summed = sum((self.whole_number, g.whole_number, self.fraction, g.fraction))
    whole = int(summed)
    remainder = summed - whole
    return '{} and {}'.format(whole, remainder)

Fraction() 类为您实现了__add__，您可以对整数和Fraction() 对象求和，它的工作原理如下它应该。

使用常量的演示:

>>> from fractions import Fraction
>>> summed = sum((2, 1, Fraction(3, 4), Fraction(2, 3)))
>>> whole = int(summed)
>>> remainder = summed - whole
>>> '{} and {}'.format(whole, remainder)
'4 and 5/12'

一个鲜为人知但方便的事实是 Python 的 int() 类型同时具有 .numerator 和 .denominator 属性，即fractions.Fraction() 类使用。如果您不使用fractions 库，您可以自己使用它:

def __add__(self, g):
    summed = 0
    for v in (self.whole_number, g.whole_number, self.fraction, g.fraction):
        summed = Fraction(summed.numerator * v.denominator +
                          v.numerator * summed.denominator,
                          summed.denominator * v.denominator)
    whole = summed._numerator // summed._denominator
    remainder = Fraction(summed.numerator * whole.denominator -
                         whole.numerator * summed.denominator,
                         summed.denominator * whole.denominator)
    return '{} and {}'.format(whole, remainder)