文章[1]的作者提到:

What will we do if we need to control access to x, make it read-only or do something else to it? Won't we have to refactor everything to the getters and setters that we avoided?

意思是：

雖然我們看到@property在控制讀寫屬性，那豈不是直接__init__就好了呢？

不是的，因?yàn)開_init__是所有的成員都是可以任意操作的。

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[2]中的結(jié)論有(括號(hào)中是翻譯):

When to use @property decorator?
When an attribute is derived from other attributes in the class, so the derived attribute will update whenever the source attributes is changed.(只讀的時(shí)候用到@property)

How to make a @property?
Make an attribute as property by defining it as a function and add the @property decorator before the fn definition.(用法是在需要被裝飾的函數(shù)前面加上@property)

When to define a setter method for the property?
Typically, if you want to update the source attributes whenever the property is set. It lets you define any other changes as well.("意思是兩個(gè)屬性如果一個(gè)需要修改，另外一個(gè)根據(jù)該屬性自動(dòng)修改，那么前者需要setter，后者僅僅@property')

[3]提到:
By using property() method, we can modify our class and implement the value constraint without any change required to the client code. So that the implementation is backward compatible.(意思是在不修改原有代碼的情況下就可以加入新的功能)

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個(gè)人理解:

@property適用于變量極其多的場(chǎng)景，這個(gè)場(chǎng)景下，有些變量需要可寫，有些變量需要只讀，這個(gè)時(shí)候__init__無(wú)法滿足需要,@property應(yīng)運(yùn)而生。

我們或許會(huì)反駁，如果是所有變量都可寫的情況呢？

此時(shí)使用__init__也可以實(shí)現(xiàn)可讀可寫的效果啊，還要"@propery以及@xxx.setter"干嘛呢？

確實(shí)如此，從讀寫效果上，此時(shí)"@propery以及@xxx.setter"和__init__是一致的，不考慮封裝的話，此時(shí)使用__init__與"@propery以及@xxx.setter"效果上是一致的。

還有一個(gè)好處是,使用@propery的話，我們可以看到右下方的函數(shù)名都可以保持一致，

讓代碼更加清晰，試想:

左側(cè)你讀代碼還要把代碼名字理解一遍，

右側(cè)所有成員函數(shù)都是def value，掃一眼就知道都是在服務(wù)于value這個(gè)參數(shù)

附錄是上面貼圖中左右兩側(cè)的代碼

#---------------------------------------------------------附錄中是[3]中的代碼-------------------------------------------------------------------------

不使用[3]

# Python program to explain property() function # Alphabet class class Alphabet: def __init__(self, value): self._value = value # getting the values def getValue(self): print('Getting value') return self._value # setting the values def setValue(self, value): print('Setting value to ' + value) self._value = value # deleting the values def delValue(self): print('Deleting value') del self._value value = property(getValue, setValue, delValue, ) # passing the value x = Alphabet('GeeksforGeeks') print(x.value) x.value = 'GfG'del x.value

使用[3]

# Python program to explain property() # function using decorator class Alphabet: def __init__(self, value): self._value = value # getting the values @propertydef value(self): print('Getting value') return self._value # setting the values @value.setter def value(self, value): print('Setting value to ' + value) self._value = value # deleting the values @value.deleter def value(self): print('Deleting value') del self._value # passing the value x = Alphabet('Peter') print(x.value) x.value = 'Diesel'del x.value

#------------------------------------------------------------------------------------------------------------------------------------------

[1]What's the point of properties in Python?

[2]Python @Property Explained – How to Use and When? (Full Examples)

[3]Python | property() function

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