python 关于@的解释

自从开始学习python，看源码的时候经常可以看到@来修饰的方法，之前一直没搞清楚。现在汇总下自己对于@的理解：

@是python的修饰符，Decorator类类似于C的预编译宏，因此在代码函数调用之前或者执行main函数之前就已经完成了编译。

我可以创建修饰类或者是修饰方法，用来修饰方法。在写一个修饰类的时候，必须要实现它的__CALL__方法。

1.修饰类（编译过程）

class decorator(object):
def __init__(self,f):
print "inside decorator.__init__"
f()
def __call__(self):
print "inside decorator.__call__"

@decorator
def aFunction():
print "inside aFunction()"

print "Finished decorating aFunction()"
aFunction()输出结果：
inside decorator.__init__
inside aFunction()
Finished decorating aFunction()
inside decorator.__call__这个是一个修饰类，我们可以看到它的编译过程，在调用之前就已经编译完成
2.修饰方法（其中可以理解参数的传递）

def decorator_maker_with_arguments(decorator_arg1, decorator_arg2):

print "I make decorators! And I accept arguments:", decorator_arg1, decorator_arg2

def my_decorator(func):
# The ability to pass arguments here is a gift from closures.
# If you are not comfortable with closures, you can assume it's ok,
# or read: http://stackoverflow.com/questions/13857/can-you-explain-closures-as-they-relate-to-python print "I am the decorator. Somehow you passed me arguments:", decorator_arg1, decorator_arg2

# Don't confuse decorator arguments and function arguments!
def wrapped(function_arg1, function_arg2) :
print ("I am the wrapper around the decorated function.\n"
"I can access all the variables\n"
"\t- from the decorator: {0} {1}\n"
"\t- from the function call: {2} {3}\n"
"Then I can pass them to the decorated function"
.format(decorator_arg1, decorator_arg2,
function_arg1, function_arg2))
return func(function_arg1, function_arg2)

return wrapped

return my_decorator

@decorator_maker_with_arguments("Leonard", "Sheldon")
def decorated_function_with_arguments(function_arg1, function_arg2):
print ("I am the decorated function and only knows about my arguments: {0}"
" {1}".format(function_arg1, function_arg2))

decorated_function_with_arguments("Rajesh", "Howard")输出结果：
I make decorators! And I accept arguments: Leonard Sheldon
I am the decorator. Somehow you passed me arguments: Leonard Sheldon
I am the wrapper around the decorated function.
I can access all the variables
- from the decorator: Leonard Sheldon
- from the function call: Rajesh Howard
Then I can pass them to the decorated function
I am the decorated function and only knows about my arguments: Rajesh Howard

由此2种方式应该可以完全理解了~