Question

我有一个类的这一部分，它取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，我不知道如何做到这一点，我假设如果分数是> = 1.任何帮助将是非常感谢

Answer 1

如果您使用fractions library，则可以对所有内容求和，然后取出分数的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__add__，您可以只对整数和Fraction()对象进行求和，这一切都可以正常工作。

使用常量进行演示：

>>> 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'

一个鲜为人知但却很方便的事实是，int()类型的Python具有.numerator和.denominator属性，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)

Answer 2

“修复”您的版本的一种方法是直接处理不正确的分数：

   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
   whole_add += numerator // denominator
   numerator -= numerator % denominator
   f=Fraction(numerator,denominator)
   return '{} and {}'.format(whole_add,f)

虽然有更有效的方法可以更直接地进行这种添加。

添加分数类python

2 个答案: