class Dog:
    species = "Canis lupus"  # 类属性
<pre class="brush:python;toolbar:false;">def __init__(self, name):
    self.name = name  # 实例属性

创建实例

dog1 = Dog("Buddy") dog2 = Dog("Max")

访问类属性

print(Dog.species) # 输出: Canis lupus print(dog1.species) # 输出: Canis lupus print(dog2.species) # 输出: Canis lupus

Dog.species = "Canis familiaris"
print(dog1.species)  # 输出: Canis familiaris
print(dog2.species)  # 输出: Canis familiaris

dog1.species = "Custom species"
print(dog1.species)  # 输出: Custom species（实例属性）
print(dog2.species)  # 输出: Canis familiaris（仍为类属性）
print(Dog.species)   # 输出: Canis familiaris

class Counter:
    count = 0  # 类属性，记录实例数量
<pre class="brush:python;toolbar:false;">def __init__(self):
    Counter.count += 1

c1 = Counter() c2 = Counter() print(Counter.count) # 输出: 2

class BadExample:
    members = []  # 错误示范：可变类属性
<pre class="brush:python;toolbar:false;">def add_member(self, name):
    self.members.append(name)

g1 = BadExample() g2 = BadExample() g1.add_member("Alice") g2.add_member("Bob") print(g1.members) # 输出: ['Alice', 'Bob'] —— 被共享了！