python class decorator

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Python decorator detailed

Adorner: Essentially a function (decorating other functions): Adding ancillary functionality to other functions.Principle: Cannot modify the source code of the decorated function Cannot modify the calling method of the decorated function Realize the knowledge reserve of the Adorner (decorator): function is variable Higher order functions Nested functions function is variable: Pass the function name as a

Application of Python development decorator

(func): # Func=index def wrapper (*args,**kwargs): If en Gine = = ' file ': If current_user[' username ': print (' already logged in ') Res=func (*args,**kwargs) return res uname=input (' User name >>: '). Strip () Pwd=inpu T (' Password >>: '). Strip () if uname = = ' Egon ' and pwd = = ' 123 ': print (' login successful ') current_user[' username ']=uname res=func (*args,**kwargs) return res Else:print (' Username or password error ') elif engi

python--Decorator

) Stop_time=time.time ()Print('run time is%s'% (stop_time-start_time)) returnResreturnThe return value of the wrapper #timmer () points to the memory address of the function wrapper () @timmerdeffoo (): Time.sleep (3) Print('From foo') foo ()With reference decoratordefAuth (driver='file'):#any parameter can be added here, with all the reference adorners up to three layers defAuth2 (func):#func fixed here, not allowed to add value, only is the memory address of the decorated function

Python's cache decorator

A simple memory cache. Can be used to cache arbitrary function methods in memory.#!/usr/bin/python ImportFunctools fromThreadingImportRlockImportLogging LOGGER= Logging.getlogger (__name__)classCachenullvalue (object):Pass_null=Cachenullvalue ()classCache (object):def __init__(Self, cache_limit=1000): Self._cache={} self._queue=[] Self.cache_limit=Cache_limit Self._lock=Rlock ()def __getitem__(self, name): With Self._lock:returnself._cache.get (name,

13-python-Decorator

the memory address of the Deco () One A - deftest1 (): -Time.sleep (3) the Print("In the test1") - - - deftest2 (): +Time.sleep (3) - Print("In the test2") + A atTimer (test1)#test1 memory address assigned to Func, returns the memory address of Deco () - Print(Timer (test1))#returns the memory address of the Deco () -Test1 = Timer (test1)#memory address assigned to Test1 -Test1 ()#equivalent to performing deco () - - timer (test2) inTest2 =timer (test2) - test2 () to + Print("--

Python Decorator II (function with parameter decoration)

#!/usr/bin/env python#_*_coding=utf-8_*_#author:xieyixue#mail: [email protected] #Created time:2015 Wednesday, July 01 00:28 03 sec def deco (func): "' defines the adorner to accept parameters, parameters for the decorated function ' ' Def _deco (*arg, **kwarg): ' ' Define method to perform the decorated function, accept 2 parameters ' ' #执行前---Execute print ("before") #执行中--and perform the decorated function ret = func (*arg, **kwarg) #执行后--and e

Python Training Decorator

1. The higher order function receives the function as the parameter, returns the function.2. Function closure3. Receive a function as a parameter, wrap it, and return a wrapper function#!/usr/env/python#-*-coding:utf-8-*- from __future__ Importprint_functiondefF1 (x):returnX*2defNew_fn (f):deffn (x):Print("Pager"+f.__name__+'()') returnf (x)returnFNA= NEW_FN (F1) (2)Print(a)Print("##################") b= F1 (2)Print(b) @new_fndefF1 (x):returnX*

Python Decorator Learning Notes

What is a python adorner?An adorner is actually a function, a function that wraps a function, returns a modified function object, assigns it the original identifier, and permanently loses access to the original function object. eg: when you need to add the same functionality to FUNC1 and FUNC2, you can add the entire function once in the outer. The way the adorner connects to a function is done with the @+ adorner name in the previous line of the func

Example of a Python decorator

() func (*args,**kwargs) stop_time=time.time () print (' Thefunc runtimeis%s ' % (stop_time-start_timereturn deco # # # # #想要哪个函数调用装饰器就在哪个头部加这个内容 # # # # @timer = = Test1 = Timer (test1) @timer def test1 (): Time.sleep (3) print (' This is TE St1 ') def test2 (name,age): Time.sleep (3) print (' This is Test2 ') print (' name:%s,age:%s '% (name,age)) test1 () #test1 Has not been changed, and the calling method has not been changed test2 (' Thieves ', 18)Above three examples if the decorated fun

Python decorator (full complement)

("index") Index (' W ', ' Z ') #执行过程  1. The interpreter interprets the Python code from the top to first load the HS1 function into memory, and then add the HS2 and ZSQ functions to the memory. 2, Encounter @zsq (HS1, HS2), the interpreter will first execute ZSQ (HS1, HS2), HS1 and HS2 as parameters to zsq assigned to zsq the formal parameters hs_1 and hs_2 (here equivalent to @zsq = ZSQ (HS1,HS2)). 3. Load the home function into memory and ret

Python Notes-Decorator supplement

():6 Print "Wrap Start"7 func ()8 Print "Wrap end\n"9 returnUpdate_wrapper (Wrapper,func)#calling the Update_wrapper methodTen One @deco A deffoo (): - """docstring for Foo""" - Print "In foo ():" the - foo () - PrintFoo.__name__ - PrintFoo.__doc__1 #!/usr/bin/env python2 fromFunctoolsImportWraps3 4 defDeco (func):5@wraps (func)#using adorners to implement6 defwrapper ():7 Print "Wrap Start"8 func ()9 Print "Wrap end\n"Ten returnwrapper One

Day5 python Decorator

, Func () is just a string of strings, and func () does not call executionStop_time =time.time ()Print("The func run time is%s"% (Stop_time-start_time)) returnDeco@timer#Test1=timer (test1)deftest1 (): Time.sleep (3) Print("In the test1") test1 ()in is 3.0149574279785156 ResultIntroduce @timer , which is equivalent to the Test1=timer (test1) statement.3. An adorner with an indeterminate number of parameters1 Import Time2 3 defTimer (func):#Timmer (test1) Func=test14 defDeco (*args,**Kwarg

Python function and variable scope and adorner decorator @ detailed

Functions and variables of the function在python程序中,函数都会创建一个新的作用域,又称为命名空间,当函数遇到变量时,Python就会到该函数的命名空间来寻找变量,因为Python一切都是对象,而在命名空间中,都是以字典形式存在着,这些变量名,函数名都是索引,而值就是,对应的变量值和函数内存地址。在python中可以用globals()查看全局变量,locals()局部变量。>>> global_v = ‘全局变量‘>>> def func():... local_v = ‘局部变量‘... print(locals()) #调用locals

Python Decorator usage examples and practical application examples

' MyFunc () called 'MyFunc () Test 6 function parameter passingCopy the Code code as follows: def deco (ARG): def _deco (func): Print arg def __deco (str): print ' before Func ' Func (str) print ' after Func ' Return __deco Return _deco @deco (' deco ')def myfunc (str):print ' MyFunc () called ', strMyFunc (' Hello ') Test 7 Unknown number of parametersCopy the Code code as follows: def deco (ARG): def _deco (func): Print arg def __deco (*args, **kwargs): print ' before Func ' Func (*args,

"24" Python decorator notes

function as a "variable", let's first talk about the mechanism of Python memory storage variables.When a variable x=1 is set, memory is considered a big house, and when it comes to a room, it will be free to place the variable value 1 into the room and affix the number x.If it is x=1,y=x, that is the variable value 1 The room will have two numbers, namely xy. :In the Python memory recycling mechanism, when

Fluent Python seventh chapter function decorator and closure learning record

that preserves the binding of a free variable that defines a function, so that when the function is called, the scope of the definition is not available, but those bindings are still available.Nonloal statementA local variable in a function can be used by a function in a function, but if an assignment statement is used, it is necessary to define the local variable as a free variable, and the function of Nonloal is to mark the variable as a free variable.There is no nonlocal in Python2 but you c

Python Decorator Initial Learning

The first step simple function1 " " simple function: Call two times " " 2 def myfunc (): 3 Print ('myfunc () called. ' )45myfunc ()6 myfunc ()The second step adorner provides additional functionality for the calling function1 " "Replace function (decoration)2 The parameter of the adornment function is the decorated function object, returning the original function object3 The material statement of the ornament; myfunc = Deco (myfunc)" "4 defDeco (func):5 Print("before MyFunc () called.")6

Python built-in decorator

1 defDeco (func):2 def_deco ():3 Print("before")4 func ()5 Print("End")6 #Return func here does not need to be returned7 return_deco#This is not _deco ()8 9 @decoTen defmyfunc (): One Print("clled") A -MyFunc ()With the parameterdefDeco (func):def_deco (A, b):Print("before") ret=func (A, b)Print("End") #Return func here does not need to be returned return_deco#This is not _deco ()@decodefMyFunc (A, b):Print("clled"Ab)returnABmyfunc (7,15)

Python Decorator Self-Understanding memo

Simple adorner code (for decorated functions with parameters and return values):#!_*_ coding=utf-8 _*_#!/usr/bin/env pythondef outer (fun): Def wrapper (Var): print "pre-decoration" Resulf = Fun (var ) print "Post Deco" return Resulf return Wrapper@outerdef Func1 (Var): print "This is Func1", var return "T He is Func1 return "Resulf = Func1 (" WLW ") print Resulf execution result: #这是Func1经过装饰后的结果装饰前this is Func1 WLW after decoration # This is the return value of the accepted function this is th

Python Iterator builder Decorator

IteratorsAn object that can directly act on a for loop is called an iterative object (iterable).An object that can be called by the next () function and continually returns the next value is called an iterator (Iterator).All iterable can be converted to iterator via the built-in function iter ().names = ITER (['Sun','IBM','Sunny'])Print(names)Print(names.__next__())Print(names.__next__())Print(names.__next__())Print(names.__next__())#first output Print iterator object#the next method for the No.

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