[Python] Design a class ‘fractions’ so that the fr

Question

[Python] Design a class ‘fractions’ so that the fractions can be directly added and subtracted like integers. For example, 2/1+3/5=13/5, and make sure that the numerator and denominator do not have a common factor greater than 1.(hint: overwrite __str__, __add__, __sub__ methods)…… 请问怎么确保分子分母的因数只有1呀~

Answer 1

import math

class Fraction:
    def __init__(self, numerator, denominator):
        if denominator == 0:
            raise ValueError("Denominator cannot be zero")
        self.numerator = numerator
        self.denominator = denominator
        self.simplify()
    
    def simplify(self):
        """Simplify the fraction by dividing both numerator and denominator by their GCD."""
        gcd = math.gcd(self.numerator, self.denominator)
        self.numerator //= gcd
        self.denominator //= gcd
    
    def __str__(self):
        return f"{self.numerator}/{self.denominator}"
    
    def __add__(self, other):
        if not isinstance(other, Fraction):
            return NotImplemented
        new_numerator = self.numerator * other.denominator + other.numerator * self.denominator
        new_denominator = self.denominator * other.denominator
        return Fraction(new_numerator, new_denominator)
    
    def __sub__(self, other):
        if not isinstance(other, Fraction):
            return NotImplemented
        new_numerator = self.numerator * other.denominator - other.numerator * self.denominator
        new_denominator = self.denominator * other.denominator
        return Fraction(new_numerator, new_denominator)
    
    def __eq__(self, other):
        if not isinstance(other, Fraction):
            return NotImplemented
        return (self.numerator == other.numerator) and (self.denominator == other.denominator)

# Example usage
frac1 = Fraction(2, 1)
frac2 = Fraction(3, 5)
print(f"{frac1} + {frac2} = {frac1 + frac2}")
print(f"{frac1} - {frac2} = {frac1 - frac2}")