python之装饰器

# def foo():
#     print("I am foo")
#
# foo = use_logging(foo)
#
# foo()
"""
use_logging(foo)
wrapper == foo
foo() == wrapper()

1.首先先执行foo被赋值为use_logging(foo)
use_logging(foo):
return wrapper
此时 foo == wrapper 
下面又执行了foo() == wrapper()
打印日志 %s is running %func.__name__ 因为use_logging(func) 中 func == foo
所以%func == foo.__name__
之后return func()
就是在返回foo()
调用foo函数：
I am foo
"""

# def use_logging(func):
#     def wrapper():
#         logging.warn("%s is running"%func.__name__)
#         return func()
#     return  wrapper
#
# @use_logging
# def foo():
#     print("I am foo")
# foo()
"""
第一次调用时func == foo
进入到函数体内部时:use_logging 
foo == wrapper
外部的foo() == wrapper()
在执行wrapper()函数中的内容 %s == func == foo
return func() == foo()
在执行foo()函数
I am foo
"""


# def day(func):
#
#     def today():
#         print("我叫杨洋")
#         return  func()
#     return today
#
# @day
# def xinqing():
#     print("心情很不错!")
#
# xinqing()

# def day(func):
#
#     def names():
#         print("我叫做杨洋")
#         return func()
#     return names
#
# @day
# def today():
#     print("今天是周六")
# today()


# def foo(name):
#     print("I am %s"%name)
#
# foo("yang")


# def use_logging(func):
#     def wrapper(*args):
#         logging.warn("%s is running"%func.__name__)
#         return func(*args)
#     return wrapper
#
# @use_logging
# def foo(name,age = 21,height = 175):
#     print("I am %s, i'am %s years old,my height is %s"%(name,age,height))
#
# foo("杨洋")
"""
首先代码执行到检测装饰器"@use_logging"
这时下面的函数名字被传递到use_logging(func) 中的 func传参中 此时 func == foo
因为执行调用了use_logging函数所以>>>>
执行调用use_logging函数里面的函数"wrapper"
wrapper函数里面返回了wrapper 这个过程称之为"闭包"
首先返回了wrapper 所以此时的foo == wrapper 
代码的下方执行了foo() 因为上面的wrapper返回了wrapper 所以此时foo() == wrapper()
执行调用wrapper() 函数里面的内容
logging.wran("%s is running"%func.__name__)因为func == foo 所以打印:
"WARNING:root:foo is running" foo == func
wrapper函数内容继续往下执行调用func()
因为func == foo 所以 func() == foo()
执行调用foo()
foo()函数内部打印
"I am foo"
整体函数执行完毕
"""

###########################传递多个参数############################

# def use_logging(func):
#     def wrapper(*args,**kwargs):
#         logging.warn("%s is running"%func.__name__)
#         return func(*args,**kwargs)
#     return wrapper
#
# def foo(name,age=21,depct="技术"):
#     print("我叫%s,我今年%s,我的职业是%s"%(name,age,depct))
#
# foo("杨洋")

##################装饰器提供参数######################
# def use_logging(level):
#     def decorator(func):
#         def wrapper(*args,**kwargs):
#             if level == "warn":
#                 logging.warn("%s is running"%func.__name__)
#             elif level == "info":
#                 logging.info("%s is running"%func.__name__)
#             return func(*args)
#         return wrapper
#     return decorator
#
# @use_logging(level="warn")
# def foo(name = "foo"):
#     print("I am %s"%name)
#
# foo()
"""
首先执行装饰器调用函数use_logging 并且将装饰器里面的level值进行赋值 level == warn
然后下面的函数名foo被执行到use_logging中 
此时跳转到use_logging函数 
执行里面的decorator(func)函数 此时func == foo
在执行内置函数里的内置函数"wrapper"
此时*args **kwargs代表接收所有传入的参数值
wrapper函数内进行判断level
因为装饰器在装饰函数use_logging的时候就已经定义了level == warn
所以进行下面的判断，level == warn  执行:
打印日志告警 传入func 变量   func == foo
之后在返回 func(*args)   func == foo func(*args) == foo(*args) foo(name = "foo")
执行调用foo函数
打印"I am %s(name)"  name == foo == I am foo
"""






import time
# def foo(fn):
#     start = time.time()  #:记录时间
#     fn()
#     run = time.time() - start
#     print(run)

# def outher(fn):  #:2:执行outher fn 传参被传入 func    fn == func
#     def inner():
#         start = time.time()
#         fn()   #:5:因为fn 传参已经被传入func 所以 fn() == func()
#         run = time.time() - start
#         print(run)
#     return inner       #:3:返回inner 给 func 因为是func调用的outher 所以inner返回给func
# @outher   #:1:func 调用 outher
# def func():
#     for i in range(99999):
#         pass
#     print("hello")
# func()   #:4:func == inner == inner()



# import time
# def decorator(func):
#     def wrapper(*args,**kwargs):
#         start_time = time.time()
#         func()
#         end_time = time.time() - start_time
#         print(end_time)
#     return wrapper
#
# @decorator    #:在装饰器这里相当于  decorator(func)
# def func():
#     time.sleep(0.8)
# func()