在 Python 类中，类变量是属于类本身的变量，所有实例共享同一内存空间。修改类变量的方式主要有两种：通过类名修改和通过实例修改，但两者的效果截然不同，需要重点区分。
1. 通过类名修改类变量（推荐）
通过类名直接修改类变量，会真正改变类变量的值，所有实例访问该变量时都会获取到更新后的值。
示例：
python
运行
class MyClass: class_var = "初始值" # 类变量 # 通过类名修改类变量 MyClass.class_var = "修改后的值" # 所有实例访问的都是修改后的值 obj1 = MyClass() obj2 = MyClass() print(obj1.class_var) # 输出：修改后的值 print(obj2.class_var) # 输出：修改后的值 print(MyClass.class_var) # 输出：修改后的值2. 通过实例修改类变量（不推荐，易混淆）
通过实例修改类变量时，不会改变类本身的变量，而是会给该实例创建一个同名的实例变量，此后该实例访问该变量时，会优先使用自己的实例变量（屏蔽类变量），而其他实例和类本身访问的仍然是原来的类变量。
示例：
python
运行
class MyClass: class_var = "初始值" # 类变量 obj1 = MyClass() obj2 = MyClass() # 通过实例 obj1 "修改" 类变量（实际是创建实例变量） obj1.class_var = "obj1的实例变量" # 实例 obj1 访问的是自己的实例变量 print(obj1.class_var) # 输出：obj1的实例变量 # 实例 obj2 和类本身访问的仍是原来的类变量 print(obj2.class_var) # 输出：初始值 print(MyClass.class_var) # 输出：初始值总结
- 通过类名修改：会全局更新类变量，影响所有实例。
- 通过实例修改：不会改变类变量，只会给该实例新增一个同名实例变量，仅影响当前实例。
实际开发中，建议始终通过类名修改类变量，避免通过实例修改导致的逻辑混淆。
https://avg.163.com/topic/detail/8126074
https://avg.163.com/topic/detail/8126272
https://avg.163.com/topic/detail/8126470
https://avg.163.com/topic/detail/8125935
https://avg.163.com/topic/detail/8126065
https://avg.163.com/topic/detail/8126263
https://avg.163.com/topic/detail/8126400
https://avg.163.com/topic/detail/8126466
https://avg.163.com/topic/detail/8125933
https://avg.163.com/topic/detail/8126049
https://avg.163.com/topic/detail/8126269
https://avg.163.com/topic/detail/8126404
https://avg.163.com/topic/detail/8126469
https://avg.163.com/topic/detail/8125931
https://avg.163.com/topic/detail/8126061
https://avg.163.com/topic/detail/8126265
https://avg.163.com/topic/detail/8126401
https://avg.163.com/topic/detail/8126465
https://avg.163.com/topic/detail/8125932
https://avg.163.com/topic/detail/8126397
https://avg.163.com/topic/detail/8126462
https://avg.163.com/topic/detail/8126054
https://avg.163.com/topic/detail/8126398
https://avg.163.com/topic/detail/8126464
https://avg.163.com/topic/detail/8126052
https://avg.163.com/topic/detail/8126258
https://avg.163.com/topic/detail/8126396
https://avg.163.com/topic/detail/8126461
https://avg.163.com/topic/detail/8125930
https://avg.163.com/topic/detail/8126045
https://avg.163.com/topic/detail/8126267
https://avg.163.com/topic/detail/8126402
https://avg.163.com/topic/detail/8126467
https://avg.163.com/topic/detail/8126261
https://avg.163.com/topic/detail/8126399
https://avg.163.com/topic/detail/8126468
https://avg.163.com/topic/detail/8125934
https://avg.163.com/topic/detail/8126050
https://avg.163.com/topic/detail/8126268
https://avg.163.com/topic/detail/8126463
