在 Python 中,定義類變數的正確方式是什麼?
類變數是在__init__方法外部宣告的變數。這些屬於靜態元素,意思在於它們屬於該類而不是類例項。這些類變數由該類的所有例項共享。類變數的示例程式碼
示例
class MyClass: __item1 = 123 __item2 = "abc" def __init__(self): #pass or something else
你將透過更多程式碼更加清晰地理解 −
class MyClass: stat_elem = 456 def __init__(self): self.object_elem = 789 c1 = MyClass() c2 = MyClass() # Initial values of both elements >>> print c1.stat_elem, c1.object_elem 456 789 >>> print c2.stat_elem, c2.object_elem 456 789 # Let's try changing the static element MyClass.static_elem = 888 >>> print c1.stat_elem, c1.object_elem 888 789 >>> print c2.stat_elem, c2.object_elem 888 789 # Now, let's try changing the object element c1.object_elem = 777 >>> print c1.stat_elem, c1.object_elem 888 777 >>> print c2.stat_elem, c2.object_elem 888 789
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