python类之间共享属性/变量

Question

class Base(object):
def __init__(self):
print("Base created")
a = "baseclass"
class ChildA(Base):
def __init__(self):
Base.__init__(self)
b = "child a"
class ChildB(Base):
def __init__(self):
super(ChildB, self).__init__()
c = "child b"
print(a)
print(b)
ChildA()
ChildB()

NameError: name 'a' is not defined

Answer 1

您的问题是试图访问局部变量而不是实例属性。

以下是你应该怎么做：

class Base():
def __init__(self):
print("Base created")
# Note that you should use `self.a` instead of `a`
self.a = "baseclass"
class ChildA(Base):
def __init__(self):
Base.__init__(self)
# Use `self.b` instead of `b`
self.b = "child a"
# Did you forget to inherit from `ChildA`?
class ChildB(ChildA):
def __init__(self):
# The `super()` call can be simplified
super().__init__()
# Use `self.c` instead of `c'
self.c = "child b"
# Access the instance variables using `self.`
print(self.c)
print(self.b)
print(self.a)

ChildA()
ChildB()

从控制台输出：

Base created
Base created
child b
child a
baseclass