Interesting example of Python decorator

Interesting example of Python decorator

Miss Liao's tutorial is too advanced to understand. Click to open the link.

 

def deco_functionNeedDoc(func):    if func.__doc__ == None :        print func, "has no __doc__, it's a bad habit."    else:        print func, ':', func.__doc__, '.'    return func@deco_functionNeedDocdef f():    print 'f() Do something'@deco_functionNeedDocdef g():    'I have a __doc__'    print 'g() Do something'f()g()print fprint g

 

 

The output of this Code is as follows:

Has no Doc, It's a bad habit.

: I have Doc. F () Do somethingg () Do something

At that time, I was dizzy. After thinking for a long time, I used to call the decorator when I called the @ decorator function. The decorator function return func, and func is the input parameter f. Modify the code at this time.

 

 

def deco_functionNeedDoc(func):    if func.__doc__ == None :        print func, "has no __doc__, it's a bad habit."    else:        print func, ':', func.__doc__, '.'    def func_1(*args, **kw):        print func.__name__,' : this is func_1'    return func_1@deco_functionNeedDocdef f():    print 'f() Do something'@deco_functionNeedDocdef g():    'I have a __doc__'    print 'g() Do something'f()g()print fprint g

 

Print the result at this time:

Has no _ doc __, it's a bad habit.
: I have a _ doc __.
F: this is func_1
G: this is func_1
Func_1
Func_1

 

At this point, the problem should be clear ~~ Just, what is the ornament ?? Under what circumstances ?? Waiting for exploration

 

Finally, I posted another super reunion, which is very interesting. I don't want to explain it, but I am sleepy. After understanding this, I can fully evaluate the basic principle of the decoration device.

 

def deco_functionNeedDoc(func1):    if func1.__name__ == "yyy" :        print func1, "the func1 == yyy"    else:        print func1, ':', func1.__doc__, '.'    def xxx() : # y + f + h + x        func1() # y + f + h + f + h        print "plus xxx"        return func1() # y + f + h + f + h    return xxxdef deco_functionNeedDocxxx(func2):    if func2.__name__ == "hhh" :        print func2, "the func2 == hhh"    else:        print func2, ':', func2.__doc__, '.'    def yyy(): # y + f + h + f + h        print "plus yyy"        func2()  # f + h        return func2() # f + h    return yyydef deco_functionNeedDochhh(func3):    if func3.__name__ == "f" :        print func3, "the func3 == f"    else:        print func3, ':', func3.__doc__, '.'    def hhh() : # = f + h        func3()  # = f        print "plus hhh"        return "Hello Wrold"    return hhh@deco_functionNeedDoc@deco_functionNeedDocxxx@deco_functionNeedDochhhdef f():    print 'print original fff'f()print "------------"print fprint "------------"print f()

The result is as follows:

 

The func3 = f
The func2 = hhh
The func1 = yyy
Plus yyy
Print original fff
Plus hhh
Print original fff
Plus hhh
Plus xxx
Plus yyy
Print original fff
Plus hhh
Print original fff
Plus hhh
------------

------------
Plus yyy
Print original fff
Plus hhh
Print original fff
Plus hhh
Plus xxx
Plus yyy
Print original fff
Plus hhh
Print original fff
Plus hhh
Hello Wrold