1.1 Closures
1, as a function of first-class objects, support assigned to variables, passed as a parameter to other functions, other functions as a return value, supports nested functions, implements __call__ class instance object method may also be used as the function is called
2, s = func -> execution of the function memory address
s = func () -> function call
3, closure: nested function, the internal variable function calls to external functions
Local variables can make a permanent memory
def outer():
a=1
def inner (): # closure function
pritn(a)
print (inner .__ closuer__) # If the result is cell is a closure function
4, a common form of closure in an internal function for external use function, a function of both the internal variable becomes a
def outer():
a = 1 # permanent memory, to prevent other programs change this variable
def inner (): # closure function
pritn(a)
return inner
inn = outer () # function points to a global memory variable
inn()
1.2 decorator
1, the role of decorator, do not want to modify the function is called, but still want to increase the functionality of the original function before and after
2. Open Closed Principle
3, the nature of decorators: closure function
. 1 DEF warpper (FUNC): 2 DEF Inner (* args, ** kwargs): . 3 # before the execution of the function do decorated . 4 RET = FUNC (* args, ** kwargs) . 5 # in the function to be decorated things to do after performing 6 return RET 7 return Inner
4、functools
from functools import wraps
def wrapper(func):
@wraps (func) # do not change the name of the function is decorative function
def inner(*args,**kwargs):
# Before the function execution garnished do
ret = func(*args,**kwargs)
# After being decorated function performs do
return right
return inner
5, decorator with parameters Layer decorator