|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 |
''' @Author: Jedi.XL @Email: xiangyangan@gmail.com @Created Time: 9:51:53 AM, Aug 29, 2019 @Github: https://github.com/jediL @Website:www.tundrazone.com ------------ 苔原带 ------------ ''' # How many times you create a class like this: class Book_old: def __init__(self, name, price): self._name = name self._price = price def get_name(self): return self._name def get_price(self): return self._price def set_name(self, value): if not isinstance(value, str): raise ValueError('Book name must be a string!') if len(value) > 80: raise ValueError('The name is too long') self._name = value def set_price(self, value): if not isinstance(value, float): raise ValueError('Price must be a float!') if value < 0 or value > 100000: raise ValueError('Price must between 0 --- 100000') self._price = value # with @property, we can do this much easiler. class Book_new: def __init__(self, name, price): self._name = name self._price = price @property def name(self): return self._name @property def price(self): return self._price @name.setter def name(self, value): if not isinstance(value, str): raise ValueError('Book name must be a string!') if len(value) > 80: raise ValueError('The name is too long') self._name = value @price.setter def price(self, value): if not isinstance(value, float): raise ValueError('Price must be a float!') if value < 0 or value > 100000: raise ValueError('Price must between 0 --- 100000') self._price = value b = Book_new("Python Cookbook", 30.0) b.name = "Effective Python" b.price = 9999999.0 print(f"name: {b.name}, price: {b.price}") # output: ValueError: Price must between 0 --- 100000 |
Python Everyday 43: @property is awesome.
