Soulution n +=1

def foo():
  foo.__dict__.setdefault('count', 0)
  foo.count += 1
  return foo.count

Python没有静态变量，但你可以通过定义一个可调用的类对象，然后将其用作函数来伪装它。也可以看看这个答案。

class Foo(object):
  # Class variable, shared by all instances of this class
  counter = 0

  def __call__(self):
    Foo.counter += 1
    print Foo.counter

# Create an object instance of class "Foo," called "foo"
foo = Foo()

# Make calls to the "__call__" method, via the object's name itself
foo() #prints 1
foo() #prints 2
foo() #prints 3

注意，__call__使类(对象)的实例可以通过自己的名称调用。这就是为什么上面调用foo()会调用类的__call__方法。从文档中可以看到:

任意类的实例都可以通过在类中定义__call__()方法来实现可调用。

你也可以考虑:

def foo():
    try:
        foo.counter += 1
    except AttributeError:
        foo.counter = 1

推理:

非常python化(“请求原谅而不是允许”) 使用异常(只抛出一次)而不是if分支(考虑StopIteration异常)

_counter = 0
def foo():
   global _counter
   _counter += 1
   print 'counter is', _counter

Python习惯上使用下划线来表示私有变量。在C语言中，在函数内部声明静态变量的唯一原因是将它隐藏在函数之外，这并不是真正的Python惯用方法。

我个人更喜欢下面的装饰。各有各的。

def staticize(name, factory):
    """Makes a pseudo-static variable in calling function.

    If name `name` exists in calling function, return it. 
    Otherwise, saves return value of `factory()` in 
    name `name` of calling function and return it.

    :param name: name to use to store static object 
    in calling function
    :type name: String
    :param factory: used to initialize name `name` 
    in calling function
    :type factory: function
    :rtype: `type(factory())`

    >>> def steveholt(z):
    ...     a = staticize('a', list)
    ...     a.append(z)
    >>> steveholt.a
    Traceback (most recent call last):
    ...
    AttributeError: 'function' object has no attribute 'a'
    >>> steveholt(1)
    >>> steveholt.a
    [1]
    >>> steveholt('a')
    >>> steveholt.a
    [1, 'a']
    >>> steveholt.a = []
    >>> steveholt.a
    []
    >>> steveholt('zzz')
    >>> steveholt.a
    ['zzz']

    """
    from inspect import stack
    # get scope enclosing calling function
    calling_fn_scope = stack()[2][0]
    # get calling function
    calling_fn_name = stack()[1][3]
    calling_fn = calling_fn_scope.f_locals[calling_fn_name]
    if not hasattr(calling_fn, name):
        setattr(calling_fn, name, factory())
    return getattr(calling_fn, name)

米格尔·安吉洛的自我重新定义解决方案甚至可以不需要任何装饰:

def fun(increment=1):
    global fun
    counter = 0
    def fun(increment=1):
        nonlocal counter
        counter += increment
        print(counter)
    fun(increment)

fun()    #=> 1
fun()    #=> 2
fun(10)  #=> 12

第二行必须进行调整，以获得有限的范围:

def outerfun():
    def innerfun(increment=1):
        nonlocal innerfun
        counter = 0
        def innerfun(increment=1):
            nonlocal counter
            counter += increment
            print(counter)
        innerfun(increment)

    innerfun()    #=> 1
    innerfun()    #=> 2
    innerfun(10)  #=> 12

outerfun()

装饰器的优点是，你不必额外注意你的施工范围。