解锁Python中神器vars内置函数的使用

# 创建一个模块
# file: my_module.py

var_in_module = "I'm in the module!"

def my_function():
    print("This is a function inside the module.")

# 主程序中使用 vars() 查看模块的属性

import my_module

# 查看模块的属性
print(vars(my_module))
# Output: {'__name__': 'my_module', '__doc__': None, 'var_in_module': "I'm in the module!", 'my_function': <function my_function at 0x7fbb42a6b670>, ...}

class MyClass:
    class_var = "I am a class variable"

    def __init__(self):
        self.instance_var = "I am an instance variable"

obj = MyClass()

# 访问类和实例属性
print(vars(MyClass))
# Output: {'__module__': '__main__', 'class_var': 'I am a class variable', ...}
print(vars(obj))
# Output: {'instance_var': 'I am an instance variable'}

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def update_age(self, new_age):
        self.age = new_age

person = Person("Alice", 30)

# 获取实例属性
print(vars(person))
# Output: {'name': 'Alice', 'age': 30}

class Dog:
    def __init__(self, name):
        self.name = name

dog = Dog("Buddy")

# 添加新属性
vars(dog)['breed'] = "Labrador"

print(vars(dog))
# Output: {'name': 'Buddy', 'breed': 'Labrador'}

class Car:
    def __init__(self, brand, model, year):
        self.brand = brand
        self.model = model
        self.year = year

my_car = Car("Toyota", "Corolla", 2020)

# 使用 vars() 动态查看对象属性
car_vars = vars(my_car)
print(car_vars)
# Output: {'brand': 'Toyota', 'model': 'Corolla', 'year': 2020}

class Laptop:
    def __init__(self, brand, model):
        self.brand = brand
        self.model = model

my_laptop = Laptop("Dell", "Inspiron")

# 动态创建新属性
vars(my_laptop)['specs'] = {'RAM': '8GB', 'Storage': '256GB SSD'}

print(vars(my_laptop))
# Output: {'brand': 'Dell', 'model': 'Inspiron', 'specs': {'RAM': '8GB', 'Storage': '256GB SSD'}}

class Book:
    __slots__ = ('title', 'author')

    def __init__(self, title, author):
        self.title = title
        self.author = author

my_book = Book("Python 101", "John Doe")

# 尝试使用 vars() 查看对象属性会引发 AttributeError
# vars(my_book)
# Output: AttributeError: 'Book' object has no attribute '__dict__'

# 在调试中使用 vars() 检查对象属性
class User:
    def __init__(self, username, email):
        self.username = username
        self.email = email

user = User("johndoe", "johndoe@example.com")

# 在调试中输出对象属性
def some_function():
    # 在函数中动态检查对象属性
    user_vars = vars(user)
    print(user_vars)
    # Output: {'username': 'johndoe', 'email': 'johndoe@example.com'}

some_function()