python装饰器入门

最新推荐文章于 2025-08-23 20:28:56 发布

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最新推荐文章于 2025-08-23 20:28:56 发布

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文章标签： python

本文通过实例详细介绍了Python中装饰器的使用方法，包括基于类和基于函数两种实现方式，并展示了如何为函数添加额外的功能，如日志记录等。此外，还探讨了带参数的装饰器的实现。

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按别人的教程弄的。

要清楚基于类和基于函数的实现的不同之处。

#!/usr/bin/env python
# -*- coding: utf-8 -*-
'''
class entryExit(object):
    def __init__(self, f):
        self.f = f

    def __call__(self):
        print "Enering", self.f.__name__
        self.f()
        print "Exited", self.f.__name__

def entryExit(f):
    def new_f():
        print "Entering", f.__name__
        f()
        print "Exited", f.__name__
    return new_f

@entryExit
def func1():
    print "inside func1()"

@entryExit
def func2():
    print "inside func2()"

func1()
func2()


class decoratorWithoutArguments(object):
    def __init__(self, f):
        print "Inside __init__()"
        self.f = f

    def __call__(self, *args):
        print "Inside __call__()"
        self.f(*args)
        print "After self.f(*args)"

@decoratorWithoutArguments
def sayHello(a1, a2, a3, a4):
    print 'sayHello arguments:', a1, a2, a3, a4

print "After decoration"

print "Preparing to call sayHello()"
sayHello("say", "hello", "argument", "list")
print "After first sayHello() call"
sayHello("a", "different", "set of", "arguments")
print "After second sayHello() call"

class decoratorWithArguments(object):
    def __init__(self, arg1, arg2, arg3):
        print "Inside __init__()"
        self.arg1 = arg1
        self.arg2 = arg2
        self.arg3 = arg3

    def __call__(self, f):
        print "Inside __call__()"
        def wrapped_f(*args):
            print "Inside wrapped_f()"
            print "Decorator arguments:", self.arg1, self.arg2, self.arg3
            f(*args)
            print "After f(*args)"
        return wrapped_f

@decoratorWithArguments("hello", "world", 42)
def sayHello(a1, a2, a3, a4):
    print 'sayHello arguments:', a1, a2, a3, a4

print "After decoration"

print "Preparing to call sayHello()"
sayHello("say", "hello", "argument", "list")
print "After first sayHello() call"
sayHello("a", "different", "set of", "arguments")
print "After second sayHello() call"

'''

def decoratorFunctionWithArguments(arg1, arg2, arg3):
    def wrap(f):
        print "Inside wrap()"
        def wrapped_f(*args):
            print "Inside wrapped_f()"
            print "Decorator arguments:", arg1, arg2, arg3
            f(*args)
            print "After f(*args)"
        return wrapped_f
    return wrap

@decoratorFunctionWithArguments("Hello", "world", 42)
def sayHello(a1, a2, a3, a4):
    print 'sayHello arguments:', a1, a2, a3, a4

print "After decoration"

print "Preparing to call sayHello()"
sayHello("say", "hello", "argument", "list")
print "After first sayHello() call"
sayHello("a", "different", "set of", "arguments")
print "After second sayHello() call"