Python中isinstance()函数判断对象类型的最佳方式详解

isinstance(object, classinfo)

x = 5
print(isinstance(x, int))  # 输出: True

y = "Hello"
print(isinstance(y, str))  # 输出: True

z = [1, 2, 3]
print(isinstance(z, list))  # 输出: True

a = 3.14
print(isinstance(a, (int, float)))  # 输出: True

class Person:
    pass

p = Person()
print(isinstance(p, Person))  # 输出: True

class Animal:
    pass

class Dog(Animal):
    pass

d = Dog()

print(isinstance(d, Animal))  # True，因为 Dog 是 Animal 的子类
print(type(d) is Animal)      # False，因为 type 只比较精确类型

def add_numbers(a, b):
    if not isinstance(a, (int, float)) or not isinstance(b, (int, float)):
        raise TypeError("参数必须为数字")
    return a + b

add_numbers(3, 4.5)  # 正确
add_numbers("3", 4)  # 抛出异常

def process_data(data):
    if isinstance(data, str):
        print("处理字符串:", data.upper())
    elif isinstance(data, list):
        print("处理列表:", sum(data))
    else:
        print("不支持的数据类型")

process_data("hello")     # 输出: 处理字符串: HELLO
process_data([1, 2, 3])   # 输出: 处理列表: 6