python （a） 创建一个类 Rational，它由两个整数 p 和 q（提名符和分母）初始化

，可以进行加、减、乘、除操作，并能够简化结果。请问，你能回答这个问题吗？

可以回答这个问题。请看下面的代码实现：

class Rational:
    def __init__(self, numerator, denominator):
        # 约分
        divisor = self.gcd(numerator, denominator)
        self.numerator = numerator // divisor
        self.denominator = denominator // divisor

    def __add__(self, other):
        new_num = self.numerator * other.denominator + other.numerator * self.denominator
        new_den = self.denominator * other.denominator
        return Rational(new_num, new_den)

    def __sub__(self, other):
        new_num = self.numerator * other.denominator - other.numerator * self.denominator
        new_den = self.denominator * other.denominator
        return Rational(new_num, new_den)

    def __mul__(self, other):
        new_num = self.numerator * other.numerator
        new_den = self.denominator * other.denominator
        return Rational(new_num, new_den)

    def __truediv__(self, other):
        new_num = self.numerator * other.denominator
        new_den = self.denominator * other.numerator
        return Rational(new_num, new_den)

    def __str__(self):
        return '{}/{}'.format(self.numerator, self.denominator)

    def gcd(self, a, b):
        if b == 0:
            return a
        return self.gcd(b, a % b)

通过上面的代码，就可以创建一个类Rational，它可以进行加、减、乘、除操作，并能够简化结果。