快捷導(dǎo)航

python裝飾器相當(dāng)于函數(shù)的調(diào)用方式

更新時(shí)間：2019年12月27日 10:27:10 作者：vwangwang

今天小編就為大家分享一篇python裝飾器相當(dāng)于函數(shù)的調(diào)用方式，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。一起跟隨小編過來看看吧

1. 普通裝飾器

 import logging
 
 1. foo = use_loggine(foo)
 def use_loggine(func):
 def wrapper():
  logging.warn("%s is running " % func.__name__)
  return func()
 return wrapper
 
 @use_loggine
 def foo():
 print "aaa"
 foo()
 print foo.__name__

2. func 需要參數(shù)：

foo = use_loggine(foo) 第一個(gè)參數(shù)就是func這個(gè)函數(shù)對(duì)象，不包含參數(shù)foo(params)

 def use_loggine(func):
 def wrapper(name):
  logging.warn("%s is running " % func.__name__)
  return func(name)
 return wrapper
 
 
 @use_loggine
 def foo(name):
 print "name is %s" % name

3. 裝飾器帶參數(shù)

 foo = use_logging('warn')(foo) 還是把被裝飾的函數(shù)當(dāng)做參數(shù)賦給裝飾器

 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.warn("%s is running" % func.__name__)
  return func(*args)
 return wrapper
 return decorator
 
 @use_logging('warn')
 def foo(name):
 print "i am %s" % name
 
 foo = use_logging('warn')(foo)
 print foo.__name__
 foo('foo')

4. 類裝飾器，還是把被裝飾的函數(shù)當(dāng)做參數(shù)賦給裝飾器

 foo = Foo(params)(func)
 
 class Foo(object):
 def __init__(self, name):
 self.name = name
 
 def __call__(self, func):
 def aa():
  print "class decorator running"
  print "name is :%s" % self.name
  func()
  print 'class decorator ending'
 return aa

 @Foo("hello")
 def bar():
 print "world"
 
 bar()
 
 @deco
 def foo()
 pass
 
 foo = deco(foo)
 
 @deco(xx)
 def foo():
 pass
 
 foo = deco(xx)(foo)

5. 類方法裝飾器

類方法裝飾器和其他裝飾器沒有什么區(qū)別，只不過在裝飾器內(nèi)部返回的函數(shù)中，第一個(gè)參數(shù)是固定的，是調(diào)用方法的對(duì)象本身，如

果是實(shí)例對(duì)象，就是self，是類方法的話，就是cls，靜態(tài)方法的話，沒有第一個(gè)參數(shù)。

 from functools import wraps

 
 def method_decor(func):
 @wraps(func)
 def wrapper(*args, **kwargs):
  try:
  u = func(*args, **kwargs)
  return u
  except Exception as e:
  args[0].bb() # args[0]就是self或者cls?？梢栽赼rgs前面定義self，更加方便u = func(self，*args, **kwargs)
  return 'an Exception raised.'
 
 return wrapper
 
 
 class Foo(object):
 
 @method_decor
 def aa(self):
  # print("This is wraped method")
  raise Exception('aa')
 
 def bb(self):
  print("This is called method")
 
 
 
 a = Foo()
 a.aa()

以上這篇python裝飾器相當(dāng)于函數(shù)的調(diào)用方式就是小編分享給大家的全部?jī)?nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持腳本之家。

您可能感興趣的文章: