Python中装饰器使用方法整理

def uppercase_decorator(func):  # 定义一个函数，其参数func是函数类型参数
    def inner():   # 嵌套函数inner
        s = func()  # 调用func()函数并将返回值赋值给s变量
        make_uppercase = s.upper()   # 将字符串转换为大写并赋值给make_uppercase
        return make_uppercase  # 结束嵌套函数func()调用，返回转换之后的字符串
    return inner  # 结束函数uppercase_decorator()调用， 返回嵌套函数inner
def say_hello():
    return 'hello world.'
if __name__=="__main__":
    say_hello2 = uppercase_decorator(say_hello)  # 调用uppercase_decorator()函数，实参是say_hello()函数，返回值say_hello2变量也是一个函数
    print(say_hello2())  # 调用say_hello2函数

def uppercase_decorator(func):
    def inner():
        s = func()
        make_uppercase = s.upper()
        return make_uppercase
    return inner
@uppercase_decorator   # 使用@uppercase_decorator装饰器声明say_hello1()函数
def say_hello1():
    return "zhang cheng."
if __name__=="__main__":
    print(say_hello1())  # 使用装饰器不需要显式调用uppercase_decorator()函数，直接调用say_hello1()函数即可。

def uppercase_decorator(func):  # 将字符串转换成大写
    def inner():
        s = func()
        make_uppercase = s.upper()
        return make_uppercase
    return inner
def backet_decorator(func): # 给字符串添加括号
    def inner():
        s = func()
        make_bracket = '(' + s + ')'
        return make_bracket
    return inner
@backet_decorator
@uppercase_decorator
def say_hello():
    return 'hello world.'
if __name__=="__main__":
    print(say_hello())

def calc(func):  # 定义装饰器函数calc(func)，其参数还是一个函数
    def wrapper(arg1):  # 定义嵌套函数wrapper(arg1)，这个函数参数列表与装饰器要注释的函数参数列表一致
        return func(arg1)
    return wrapper
@calc
def square(n):
    return n * n
@calc
def abs(n):
    return n if n > 0 else -n
if __name__=="__main__":
    print(f"3's square is {square(3)}")
    print(f"-30's absulate is {abs(-30)}")

from functools import wraps

def add_decorator(func):
    def inner():
        """
        This is a decorator.
        :return:
        """
        func()
        pass
    return inner
@add_decorator
def add():
    """
    This is a add.
    :return:
    """
    pass
if __name__=="__main__":
    print(add.__name__)
    print(add.__doc__)

from functools import wraps
def add_decorator(func):
    @wraps(func)
    def inner():
        """
        This is a decorator.
        :return:
        """
        func()
        pass
    return inner
@add_decorator
def add():
    """
    This is a add.
    :return:
    """
    pass
if __name__=="__main__":
    print(add.__name__)
    print(add.__doc__)

from functools import wraps
def add_deco(z):
    def add_decorator(func):
        @wraps(func)
        def inner(x, y):
            return z + func(x, y)
        return inner
    return add_decorator
@add_deco(z=10)
def add(x, y):
    return x + y
if __name__=="__main__":
    print(add(5, 10))