python创建实例中类属性的变化

>>> class a:

    list = []

>>> y = a()

>>> x = a()

>>> x.list = []

>>> y.list = []

>>> x.list.append(1)

>>> y.list.append(2)

>>> x.list.append(3)

>>> y.list.append(4)

>>> print(x.list)

[1, 3]

>>> print(y.list)

[2, 4]

>>> class a:

    string = ''

>>> x = a()

>>> y = a()

>>> x.string += 'x'

>>> y.string += 'y'

>>> x.string

'x'

>>> y.string

'y'