Python中callable方法的使用小结

callable(object)

# 检查内置函数是否可调用
print(callable(len))  # 输出: True

# 检查自定义函数是否可调用
def my_function():
    pass

print(callable(my_function))  # 输出: True

# 检查类是否可调用
class MyClass:
    def __call__(self):
        pass

print(callable(MyClass))  # 输出: True

# 检查类实例是否可调用
instance = MyClass()
print(callable(instance))  # 输出: True

# 检查普通对象是否可调用
obj = object()
print(callable(obj))  # 输出: False

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

    def __call__(self, greeting):
        return f"{greeting}, {self.name}!"

# 创建 Greeter 类的实例
greeter = Greeter("Alice")

# 检查实例是否可调用
print(callable(greeter))  # 输出: True

# 调用实例
print(greeter("Hello"))  # 输出: Hello, Alice!

def execute_if_callable(obj):
    if callable(obj):
        return obj()
    else:
        return "Object is not callable"

# 测试函数
print(execute_if_callable(my_function))  # 输出: None
print(execute_if_callable(42))  # 输出: Object is not callable

def process_with_callback(callback):
    if callable(callback):
        callback()
    else:
        print("Provided callback is not callable")

# 测试回调函数
def my_callback():
    print("Callback executed")

process_with_callback(my_callback)  # 输出: Callback executed
process_with_callback(42)  # 输出: Provided callback is not callable

class Interface:
    def required_method(self):
        pass

class Implementation:
    def required_method(self):
        print("Method implemented")

# 验证实现类
def validate_interface(obj, method_name):
    method = getattr(obj, method_name, None)
    if callable(method):
        return True
    else:
        return False

impl = Implementation()
print(validate_interface(impl, 'required_method'))  # 输出: True
print(validate_interface(impl, 'missing_method'))  # 输出: False