python

hrh1023

1. class Fraction:
   
2.     def __init__(self, a, b):
   
3.         self.numerator = a
   
4.         self.denominator = b
   
5. 
   
6.     def __eq__(self, other):
   
7.         return(self.numerator * other.denominator == self.denominator * other.numerator)
   
8. 
   
9.     def __str__(self):
   
10.         return str(self.numerator) + " / " + str(self.denominator)
    
11. 
    
12.     def __mul__(self, other):
    
13.         return int(self.numerator * other.denominator == self.denominator * other.numerator)

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x = Fraction(1, 2)
y = Fraction(3, 5)
print(x * x) # should be 1 / 4, or any fraction equal to this
print(x * y) # should be 3 / 10, or any fraction equal to this






怎么样才可以让那个最后验算的结果不是false 而是数字啊

qiuyouzhi

1. return int(...)

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hrh1023

qiuyouzhi 发表于 2021-2-3 21:22

你好
return int(self.numerator+other.numerator == self.denominator+other.denominator)
我这样输入后 最后结果变成两个0了 请问还有哪里出错了吗

qiuyouzhi

hrh1023 发表于 2021-2-3 21:33
你好
return int(self.numerator+other.numerator == self.denominator+other.denominator)
我这样输 ...

蛤？
我这里是1和0

hrh1023

qiuyouzhi 发表于 2021-2-3 21:59
蛤？
我这里是1和0

可是答案应该要是1/4 和3/10

qiuyouzhi

hrh1023 发表于 2021-2-3 22:03
可是答案应该要是1/4 和3/10

这是我以前写过的一个简陋分数类，你可以参考一下：

1. import math
   
2. from copy import deepcopy
   
3. 
   
4. class Fraction:
   
5.     """一个简单的分数类，模仿fractions.Fraction"""
   
6. 
   
7.     def __init__(self, num, den = 1):
   
8.         if isinstance(num, float):
   
9.             self.convert(float(num), flag = True)
   
10.             return
    
11.         elif isinstance(num, str):
    
12.             num, den = map(int, num.split('/'))
    
13.         self.numerator = num
    
14.         self.denominator = den
    
15.         self._rof()
    
16. 
    
17.     def convert(self, obj = None, flag = False):
    
18.         """
    
19.         将一个数字转换为Fraction类型
    
20.         """
    
21.         if isinstance(obj, int):
    
22.             return Fraction(obj)
    
23.         elif isinstance(obj, float):
    
24.             res = str(obj).replace('.', '')
    
25.             den = int("1" + ((len(res) - 1) * "0"))
    
26.             fc = Fraction(int(res), den)
    
27.             if not flag:
    
28.                 return fc
    
29.             else:
    
30.                 self.numerator, self.denominator = fc.numerator, fc.denominator
    
31.         else:
    
32.             raise ValueError("Object's type is wrong")
    
33.             
    
34. 
    
35.     # 约分函数, reduction of a fraction
    
36.     def _rof(self):
    
37.         print(self.numerator, self.denominator)
    
38.         gcd = math.gcd(self.numerator, self.denominator)
    
39.         self.numerator //= gcd
    
40.         self.denominator //= gcd
    
41.         if self.numerator == self.denominator:
    
42.             return 1.0
    
43. 
    
44.     # 通分函数, reduction of fractions to a common denominator
    
45.     def _rofcd(self, other):
    
46.         fc1 = deepcopy(self)
    
47.         fc2 = deepcopy(other)
    
48.         fc1.denominator *= fc2.denominator
    
49.         fc1.numerator *= fc2.denominator
    
50.         fc2.denominator *= self.denominator
    
51.         fc2.numerator *= self.denominator
    
52.         return fc1, fc2
    
53. 
    
54.     def __setattr__(self, key, value):
    
55.         if key == "denominator" and value == 0:
    
56.             raise ValueError("The denominator can't be zero")
    
57.         else:
    
58.             self.__dict__[key] = value
    
59. 
    
60.     def __add__(self, other):
    
61.         if isinstance(other, Fraction):
    
62.             if self.denominator != other.denominator:
    
63.                 fc1, fc2 = self._rofcd(other)
    
64.             else:
    
65.                 fc1 = deepcopy(self)            
    
66.         else:
    
67.             fc1 = deepcopy(self)
    
68.             fc2 = self.convert(other)
    
69. 
    
70.         fc1.numerator += fc2.numerator
    
71.         k = fc1._rof()
    
72.         return k if k else fc1
    
73. 
    
74.     def __sub__(self, other):
    
75.         if isinstance(other, Fraction):
    
76.             if self.denominator != other.denominator:
    
77.                 fc1, fc2 = self._rofcd(other)
    
78.                 fc1.numerator -= fc2.numerator
    
79.                 fc1._rof()
    
80.                 return fc1
    
81.         elif isinstance(other, (float, int)):
    
82.             return self.numerator / self.denominator - other
    
83. 
    
84.     def __mul__(self, other):
    
85.         if isinstance(other, Fraction):
    
86.             num = self.numerator * other.numerator
    
87.             den = self.denominator * other.denominator
    
88.             return Fraction(num, den)
    
89.         elif isinstance(other, (float, int)):
    
90.             return self.numerator / self.denominator * other
    
91.         
    
92.     def __truediv__(self, other):
    
93.         if isinstance(other, Fraction):
    
94.             fc = deepcopy(other)
    
95.             fc.numerator, fc.denominator = fc.denominator, fc.numerator
    
96.             return self * fc
    
97.         elif isinstance(other, (float, int)):
    
98.             return self.numerator / self.denominator / other
    
99.    
    
100.     def __float__(self):
     
101.         return self.numerator / self.denominator
     
102. 
     
103.     def __repr__(self):
     
104.         return f"Fraction({self.numerator}, {self.denominator})"
     
105. 
     
106.     __str__ = __repr__
     
107. 
     
108. x = Fraction(1, 2)
     
109. y = Fraction(3, 5)
     
110. print(x * x) # should be 1 / 4, or any fraction equal to this
     
111. print(x * y) # should be 3 / 10, or any fraction equal to this

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hrh1023

qiuyouzhi 发表于 2021-2-3 22:16
这是我以前写过的一个简陋分数类，你可以参考一下：

谢谢

qiuyouzhi

hrh1023 发表于 2021-2-3 22:28
谢谢

如果问题已解决，请设置【最佳答案】

°蓝鲤歌蓝

1. class Fraction:
   
2.     def __init__(self, a, b):
   
3.         self.numerator = a
   
4.         self.denominator = b
   
5. 
   
6.     def __eq__(self, other):
   
7.         return (self.numerator == other.numerator) and (
   
8.             self.denominator == other.denominator
   
9.         )
   
10. 
    
11.     def __str__(self):
    
12.         return str(self.numerator) + "/" + str(self.denominator)
    
13. 
    
14.     def __mul__(self, other):
    
15.         return Fraction(
    
16.             self.numerator * other.numerator, self.denominator * other.denominator
    
17.         )
    

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代码稍微改一下就好了。不过没实现约数，你自己试试看。
而且你的图里问题不是两个分数相加吗？ 怎么写出来却是要分数相乘啊？

kogawananari

1.     def __mul__(self, other):
   
2.         return Fraction(self.numerator * other.numerator, self.denominator * other.denominator)
   
3.     def __add__(self, other):
   
4.         if self.denominator == other.denominator:
   
5.             return Fraction(self.numerator + other.numerator, self.denominator)
   
6.         return Fraction(self.numerator*other.denominator, self.denominator*other.denominator) + Fraction(other.numerator*self.denominator, other.denominator*self.denominator)
   
7.    

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°蓝鲤歌蓝

1. class ZeroDenominatorError(ArithmeticError):
   
2.     pass
   
3. 
   
4. 
   
5. class Fraction:
   
6.     def __init__(self, a, b):
   
7.         self.numerator = a
   
8.         self.denominator = b
   
9. 
   
10.         self.__symbol = 1
    
11. 
    
12.         if a * b < 0:
    
13.             self.__symbol = 0
    
14. 
    
15.     def __setattr(self, name, value):
    
16.         if name == "denominator" and value == 0:
    
17.             raise ZeroDenominatorError("denominator by zero")
    
18.         return super().__setattr(self, name, value)
    
19. 
    
20.     # -self
    
21.     def __neg__(self):
    
22.         a, b = self.numerator, self.denominator
    
23.         if self.__symbol:
    
24.             return Fraction(a, b)
    
25.         return Fraction(abs(a), abs(b))
    
26. 
    
27.     # +self
    
28.     def __pos__(self):
    
29.         return self
    
30. 
    
31.     def __str__(self):
    
32.         a, b = self.numerator, self.denominator
    
33.         if a == 0:
    
34.             return "0"
    
35.         return "-" * abs(self.__symbol - 1) + f"{abs(a)}/{abs(b)}"
    
36. 
    
37.     def __repr__(self):
    
38.         ...
    
39. 
    
40.     __repr__ == __str__
    
41. 
    
42.     # +
    
43.     def __add__(self, other):
    
44.         a, b = self.numerator, self.denominator
    
45.         c, d = other.numerator, other.denominator
    
46.         if a == 0:
    
47.             return Fraction(c, d)
    
48.         if c == 0:
    
49.             return Fraction(a, b)
    
50. 
    
51.         ad = a * d
    
52.         bc = b * c
    
53.         bd = b * d
    
54. 
    
55.         return Fraction(ad + bc, bd)
    
56. 
    
57.     # -
    
58.     def __sub__(self, other):
    
59.         a, b = self.numerator, self.denominator
    
60.         c, d = other.numerator, other.denominator
    
61.         if a == 0:
    
62.             return -Fraction(c, d)
    
63.         if c == 0:
    
64.             return Fraction(a, b)
    
65. 
    
66.         ad = a * d
    
67.         bc = b * c
    
68.         bd = b * d
    
69. 
    
70.         return Fraction(ad + bc, bd)
    
71. 
    
72.     # *
    
73.     def __mul__(self, other):
    
74.         return Fraction(
    
75.             self.numerator * other.numerator, self.denominator * other.denominator
    
76.         )
    
77. 
    
78.     # /
    
79.     def __truediv__(self, other):
    
80.         if other.numerator == 0:
    
81.             raise ZeroDivisionError("division by zero")
    
82.         ad, bc = self.numerator * other.denominator, self.denominator * other.numerator
    
83. 
    
84.         return Fraction(ad, bc)
    
85. 
    
86.     # int(self)
    
87.     def __int__(self):
    
88.         return int(self.numerator / self.denominator)
    
89. 
    
90.     # float(self)
    
91.     def __float__(self):
    
92.         return self.numerator / self.denominator
    
93. 
    
94.     #  !=
    
95.     def __ne__(self, other) -> bool:
    
96.         if isinstance(other, Fraction):
    
97.             return str(self) != str(other)
    
98.         return True
    
99. 
    
100.     # ==
     
101.     def __eq__(self, other):
     
102.         if isinstance(other, Fraction):
     
103.             return str(self) == str(other)
     
104.         return False
     
105. 
     
106.     # <
     
107.     def __lt__(self, other) -> bool:
     
108.         if isinstance(other, Fraction):
     
109.             return float(self) < float(other)
     
110.         raise TypeError(
     
111.             f"'<' not supported between instances of 'Fraction' and {type(other)}"
     
112.         )
     
113. 
     
114.     # <=
     
115.     def __le__(self, other) -> bool:
     
116.         if isinstance(other, Fraction):
     
117.             return float(self) <= float(other)
     
118.         raise TypeError(
     
119.             f"'<=' not supported between instances of 'Fraction' and {type(other)}"
     
120.         )
     
121. 
     
122.     # >
     
123.     def __gt__(self, other) -> bool:
     
124.         if isinstance(other, Fraction):
     
125.             return float(self) > float(other)
     
126.         raise TypeError(
     
127.             f"'>' not supported between instances of 'Fraction' and {type(other)}"
     
128.         )
     
129. 
     
130.     # >=
     
131.     def __ge__(self, other) -> bool:
     
132.         if isinstance(other, Fraction):
     
133.             return float(self) >= float(other)
     
134.         raise TypeError(
     
135.             f"'>=' not supported between instances of 'Fraction' and {type(other)}"
     
136.         )
     
137. 
     
138.     # abs(self)
     
139.     def __abs__(self):
     
140.         a, b = self.numerator, self.denominator
     
141.         if self.__symbol:
     
142.             return Fraction(a, b)
     
143.         return Fraction(-a, b)
     
144. 
     
145.     # bool(self)
     
146.     def __bool__(self):
     
147.         if self.numerator == 0:
     
148.             return False
     
149.         return True
     
150. 
     

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这个的功能雏形差不多了，约分没实现