python装饰器代码深入讲解

def say():
 print('Nice day')

say()
# 这个函数的输出为：
Nice day

def say():
 print('****************')
 print('Nice day')

say()

def say():
 print('Nice day')

def outer(): # 重新定义一个新函数
 print('****************') # 处理新的逻辑
 say() # 再调用原来的函数

outer()
# 现在的输出为：
'''
****************
Nice day
'''

def say():
 print('Nice day')

def talk():
 print('I am talk')

def outer(func): # 接收一个函数
 print('****************') # 处理新的逻辑
 func() # 调用传递过来的函数

outer(talk) # 把talk函数作为参数传递过去
# 输出结果如下：
'''
****************
I am talk
'''

def say():
 print('Nice day')

def outer(func):
 def inner():
 print('****************')
 func() # 相当于 say()
 return inner

s = outer(say) # 相当于 s = inner
s() # 相当于 inner()

def outer(func):
 def inner():
 print('****************')
 func()
 return inner

@outer # 用outer装饰say
def say():
 print('Nice day')

say() # 调用say函数

# 带参数的装饰器
def outer(func):
 def inner(name):
 func(name)
 return inner

@outer
def say(name):
 print('name is %s.' % (name))

say('dandan')
# name is dandan.

# 带不定参数的装饰器
def outer(func):
 def inner(*args, **kwargs):
 func(*args, **kwargs)
 return inner

@outer
def say(name, age):
 print('name is %s, age is %d.' % (name, age))

@outer
def talk(name, age, hobby):
 print('name is %s, age is %d, hobby is %s.' % (name, age, hobby))

say('dandan', 18)
talk('dandan', 18, 'Coding')
'''
name is dandan, age is 18.
name is dandan, age is 18, hobby is Coding.
'''

# 多个装饰器
def outer(func):
 def inner(*args, **kwargs):
 print('****************')
 func(*args, **kwargs)
 return inner

def outer2(func):
 def inner2(*args, **kwargs):
 print('这里有1w+新功能')
 func(*args, **kwargs)
 return inner2

@outer
@outer2
def say(name, age):
 print('name is %s, age is %d.' % (name, age))

@outer
@outer2
def talk(name, age, hobby):
 print('name is %s, age is %d, hobby is %s.' % (name, age, hobby))

say('dandan', 18)
talk('dandan', 18, 'Coding')
'''
****************
这里有1w+新功能
name is dandan, age is 18.
****************
这里有1w+新功能
name is dandan, age is 18, hobby is Coding.
'''