问题描述
Stackoverflow大家好!
我有问题。我正在尝试更改一个实例变量(它本身是一个类实例),由于某种原因,它为原始类的所有实例都更改了相同的实例变量。
代码如下:
#create State class
class State(object):
awake = False
#Set Person Class
class Person(object):
state = State()
#create person instences
jack = Person()
jill = Person()
print(jack.state.awake)
print(jill.state.awake)
#wake jill only
jill.state.awake = True
print("")
print(jack.state.awake)
print(jill.state.awake)
输出:
False
False
True
True
我只想唤醒吉尔。
解决方法
要使awake
和state
作为实例变量,它们必须绑定到self
实例,而不是在类级别。否则,类变量是静态的,换句话说,在该类的所有实例之间共享状态。
class State:
def __init__(self):
self.awake = False
class Person:
def __init__(self):
self.state = State()
然后按照您的描述进行操作
>>> jack = Person()
>>> jill = Person()
>>> jack.state.awake
False
>>> jill.state.awake
False
>>> jill.state.awake = True
>>> jack.state.awake
False
>>> jill.state.awake
True
,
#create State class
class State(object):
def __init__(self):
self.awake = False
#Set Person Class
class Person(object):
def __init__(self):
self.state = State()
#create person instences
jack = Person()
jill = Person()
print(jack.state.awake)
print(jill.state.awake)
#wake jill only
jill.state.awake = True
print("")
print(jack.state.awake)
print(jill.state.awake)