Python之装饰器笔记

概述：

用于管理和增强函数和类行为的代码

提供一种在函数或类定义中插入自动运行代码的机制

特点  更明确的语法、更高的代码可维护性、更好的一致性

编写

函数基础： 将函数赋给变量、将函数作为参数传递、函数嵌套及跨域访问

函数定义装饰器 通用性更好

 """函数定义装饰器"""
 # 通用性更好

 # 参数化装饰器
 def tags(tag):
     def tag_decorator(func):
         def wrapper(*args, **kwargs):
             return f'<{tag}>{func(*args, **kwargs)}</{tag}>'
         return wrapper
     return tag_decorator

 def p_decorator(func):
     def wrapper(*args, **kwargs):
         return '<p>'+func(*args, **kwargs)+'</p>'

     return wrapper

 def div_decorator(func):
     def wrapper(*args, **kwargs):
         return '<div>{}</div>'.format(func(*args, **kwargs))

     return wrapper

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

     @p_decorator
     def get_name(self):
         return self.name.upper()

 @tags('p')
 # @p_decorator
 def get_text():
     return '欢迎学习优品课堂课程'

 @tags('div')
 @tags('p')
 # @div_decorator
 # @p_decorator
 def get_upper_text(text):
     return text.upper()

 if __name__ == '__main__':
     print(get_text())
     # < p > 欢迎学习优品课堂课程 < / p >
     print(get_upper_text('www.codeclassroom.com'))
     # < div > < p > WWW.CODECLASSROOM.COM < / p > < / div >
     s = Student('Mike')
     print(s.get_name())
     # < p > MIKE < / p >

类定义装饰器

装饰器参数

 """类定义装饰器"""

 class P:
     def __init__(self, func):
         self.func = func

     def __call__(self, *args, **kwargs):
         return '<p>' + self.func(*args, **kwargs) + '</p>'

 class Student:
     def __init__(self, name):
         self.name = name
     # @P 会出现错误
     def get_name(self):
         return self.name.upper()

 @P
 def get_text():
     return '欢迎学习优品课堂课程'
 @P
 def get_upper_text(text):
     return text.upper()

 if __name__ == '__main__':
     print(get_text())
     # < p > 欢迎学习优品课堂课程 < / p >
     print(get_upper_text('www.codeclassroom.com'))
     # < p > WWW.CODECLASSROOM.COM < / p >
     s = Student('John')
     print(s.get_name())
     # JOHN