3

我在这里使用类来输入分数（当给定分子和分母时），以及将两个分数相加和相乘。由于某种原因，导入的分数模块仅适用于部分程序；gcd 方法有效，但 Fraction 方法（当给定两个数字时，放入分数格式）不起作用，而是抛出 NameError （具体来说，“未定义全局名称'Fractions'”）。

我究竟做错了什么？我对 Python 比较陌生，如果有任何关于如何使这段代码更紧凑、有更多异常的建议，我将不胜感激。

这是我的代码：

import fractions

class FractionClass:
    # Initialize starting numerator and denominator.
    n = 0
    d = 0
    def __init__(self, numerator, denominator):
        self.n = numerator
        self.d = denominator

    # Function that adds fractions, whichs throws NameError if gcd() doesn't work!  
    def add_fractions(self, other):
        try:
            sum_numerator = self.n + other.n
            sum_denominator = fractions.gcd(self.d, other.d)
            return(sum_numerator, sum_denominator)
        except NameError:
            print("Methods aren't defined.")

    # Function that multiplies fractions, whichs throws NameError if gcd() doesn't work!    
    def multiply_fractions(self, other):
        try:
            product_numerator = self.n * other.n
            product_denominator = self.d * other.d
            return(product_numerator, product_denominator)
         except NameError:
            print("Methods aren't defined.")

    # Enter input function.
def user_input():
    try:
        print("Enter a numerator and denominator:")
        n, d = [int(x) for x in input().split()]
        print("Enter a numerator and denominator:")
        n2, d2 = [int(x) for x in input().split()]
        # Check used to debug for denominators that aren't the minimum of 1 (0 can't be divided!)
        check = 1 / d 
        check = 1 / d2 
        # print(check)

        # Exception for d = 0.
    except ZeroDivisionError:
        print("\n You didn't enter the minimum denominator.")
        print("Set denominator to minimum default.")
        d = 1
        # Exception for not entering a space in between numbers.
    except UnboundLocalError:
        print("You didn't enter your numbers in properly! Try again.")
        # Exception for not entering all required.
    except NameError:
        print("\n You didn't enter two numbers.")
        # Exception for user input both or one of them, not being integers.
    except TypeError:
        print("\n You didn't enter all valid numbers.")
        # General exception case.
    except:
        print("Something went wrong!")

    fract = FractionClass(n,d)
    another_fraction = FractionClass(n2, d2)
    total_sum = fract.add_fractions(another_fraction)
    # Unpacks total sum tuple.
    # Puts in fraction format.
    sum_numerator, sum_denominator = total_sum
    add_output = fractions.Fraction(sum_numerator, sum_denominator)
    total_product = fract.multiply_fractions(another_fraction)
    # Unpacks product sum tuple.
    # Puts in fraction format.
    product_numerator, product_denominator = total_product
    multiply_output = fractions.Fraction(product_numerator, product_denominator)
    print(add_output, multiply_output)
4

2 回答 2

7

您不需要自己的类来乘以两个分数：

>>> from fractions import Fraction as F
>>> F("1/2")
Fraction(1, 2)
>>> F("3/4")
Fraction(3, 4)
>>> F("1/2") * F("3/4")
Fraction(3, 8)
>>> F("1/2") + F("3/4")
Fraction(5, 4)
>>> F(5, 8) + F(4, 7)
Fraction(67, 56)

至于您提到的错误，这不太可能，因为您的代码中的任何地方都没有名称“分数”，并且您没有发布回溯。您很可能正在运行一些旧版本的代码。

于 2012-12-10T22:52:28.153 回答
0

第 26 行还有一个空格：

         except NameError:

它应该是

        except NameError:

您还应该检查并修复缩进。否则，就没有实体——没有任何东西被调用。

于 2012-12-10T22:35:51.483 回答