An interesting example of Python decorators and an exploration of python decorations

An interesting example of Python decorators and an exploration of python decorations

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:

<Function f at 0x0238F930> has noDoc, It's a bad habit.

<Function g at 0x0238F8B0>: I haveDoc. F () Do somethingg () Do something

<Function f at 0x0238F930>

<Function g at 0x0238F8B0>

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:

<Function f at 0x023CF930> has no _ doc __, it's a bad habit.
<Function g at 0x023CF8B0>: 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:

<Function f at 0x0000a2b938> the func3 = f
<Function hhh at 0x0000a2b9b0> the func2 = hhh
<Function yyy at 0x0000a2ba28> 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
------------
<Function xxx at 0x0000a2baa0>
------------
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