在Python中,如果不使用traceback模块,是否有一种方法可以从函数内部确定函数的名称?

假设我有一个模块foo和一个功能栏。当执行foo.bar()时,是否有一种方法让bar知道bar的名字?或者更好的是,foo。酒吧的名字吗?

#foo.py  
def bar():
    print "my name is", __myname__ # <== how do I calculate this at runtime?

当前回答

我用自己的方法在多重继承场景中安全地调用super(我把所有代码都放在这里)

def safe_super(_class, _inst):
    """safe super call"""
    try:
        return getattr(super(_class, _inst), _inst.__fname__)
    except:
        return (lambda *x,**kx: None)


def with_name(function):
    def wrap(self, *args, **kwargs):
        self.__fname__ = function.__name__
        return function(self, *args, **kwargs)
return wrap

示例用法:

class A(object):

    def __init__():
        super(A, self).__init__()

    @with_name
    def test(self):
        print 'called from A\n'
        safe_super(A, self)()

class B(object):

    def __init__():
        super(B, self).__init__()

    @with_name
    def test(self):
        print 'called from B\n'
        safe_super(B, self)()

class C(A, B):

    def __init__():
        super(C, self).__init__()

    @with_name
    def test(self):
        print 'called from C\n'
        safe_super(C, self)()

测试:

a = C()
a.test()

输出:

called from C
called from A
called from B

在每个@with_name修饰的方法中,您可以访问self。__fname__作为当前函数名。

其他回答

有几种方法可以达到相同的效果:

import sys
import inspect

def what_is_my_name():
    print(inspect.stack()[0][0].f_code.co_name)
    print(inspect.stack()[0][3])
    print(inspect.currentframe().f_code.co_name)
    print(sys._getframe().f_code.co_name)

注意inspect。堆栈调用比替代方法慢数千倍:

$ python -m timeit -s 'import inspect, sys' 'inspect.stack()[0][0].f_code.co_name'
1000 loops, best of 3: 499 usec per loop
$ python -m timeit -s 'import inspect, sys' 'inspect.stack()[0][3]'
1000 loops, best of 3: 497 usec per loop
$ python -m timeit -s 'import inspect, sys' 'inspect.currentframe().f_code.co_name'
10000000 loops, best of 3: 0.1 usec per loop
$ python -m timeit -s 'import inspect, sys' 'sys._getframe().f_code.co_name'
10000000 loops, best of 3: 0.135 usec per loop

2021年8月更新(原文章为Python2.7编写)

Python 3.9.1 (default, Dec 11 2020, 14:32:07)
[GCC 7.3.0] :: Anaconda, Inc. on linux

python -m timeit -s 'import inspect, sys' 'inspect.stack()[0][0].f_code.co_name'
500 loops, best of 5: 390 usec per loop
python -m timeit -s 'import inspect, sys' 'inspect.stack()[0][3]'
500 loops, best of 5: 398 usec per loop
python -m timeit -s 'import inspect, sys' 'inspect.currentframe().f_code.co_name'
2000000 loops, best of 5: 176 nsec per loop
python -m timeit -s 'import inspect, sys' 'sys._getframe().f_code.co_name'
5000000 loops, best of 5: 62.8 nsec per loop

print(inspect.stack()[0].function)似乎也可以工作(Python 3.5)。

这实际上是由这个问题的其他答案推导出来的。

以下是我的看法:

import sys

# for current func name, specify 0 or no argument.
# for name of caller of current func, specify 1.
# for name of caller of caller of current func, specify 2. etc.
currentFuncName = lambda n=0: sys._getframe(n + 1).f_code.co_name


def testFunction():
    print "You are in function:", currentFuncName()
    print "This function's caller was:", currentFuncName(1)    


def invokeTest():
    testFunction()


invokeTest()

# end of file

与使用inspect.stack()相比,这个版本可能的优势是它应该快数千倍[参见Alex Melihoff关于使用sys._getframe()与使用inspect.stack()的文章和计时]。

@jeff-laughlin的回答很漂亮。我对它进行了轻微的修改,以达到我认为的目的:跟踪函数的执行,并捕获参数列表以及关键字参数。谢谢你@jeff-laughlin!

from functools import wraps                                                                                                                                                                                                     
import time                                                                                                                                                                                                                     
                                                                                                                                                                                                                                
def named(func):                                                                                                                                                                                                                
    @wraps(func)                                                                                                                                                                                                                
    def _(*args, **kwargs):                                                                                                                                                                                                     
        print(f"From wrapper function: Executing function named: {func.__name__}, with arguments: {args}, and keyword arguments: {kwargs}.")                                                                                    
        print(f"From wrapper function: {func}")                                                                                                                                                                                 
        start_time = time.time()                                                                                                                                                                                                
        return_value = func(*args, **kwargs)                                                                                                                                                                                    
        end_time = time.time()                                                                                                                                                                                                  
        elapsed_time = end_time - start_time                                                                                                                                                                                    
        print(f"From wrapper function: Execution of {func.__name__} took {elapsed_time} seconds.")                                                                                                                              
        return return_value                                                                                                                                                                                                     
    return _                                                                                                                                                                                                                    
                                                                                                                                                                                                                                
@named                                                                                                                                                                                                                          
def thanks(message, concepts, username='@jeff-laughlin'):                                                                                                                                                                       
    print(f"From inner function: {message} {username} for teaching me about the {concepts} concepts of closures and decorators!")                                                                                               
                                                                                                                                                                                                                                
thanks('Thank you', 'two', username='@jeff-laughlin')                                                                                                                                                                           
print('-'*80)                                                                                                                                                                                                                   
thanks('Thank you', 'two', username='stackoverflow')
print(thanks) 

From wrapper function: Executing function named: thanks, with arguments: ('Thank you', 'two'), and keyword arguments: {'username': '@jeff-laughlin'}. From wrapper function: <function thanks at 0x7f13e6ceaa60> From inner function: Thank you @jeff-laughlin for teaching me about the two concepts of closures and decorators! From wrapper function: Execution of thanks took 2.193450927734375e-05 seconds. -------------------------------------------------------------------------------- From wrapper function: Executing function named: thanks, with arguments: ('Thank you', 'two'), and keyword arguments: {'username': 'stackoverflow'}. From wrapper function: <function thanks at 0x7f13e6ceaa60> From inner function: Thank you stackoverflow for teaching me about the two concepts of closures and decorators! From wrapper function: Execution of thanks took 7.152557373046875e-06 seconds. <function thanks at 0x7f13e6ceaca0>

最让我惊讶的是,有一种方法可以在运行时拦截函数,检查它们,并基于此采取一些操作。另一件令人惊讶的事情是内部函数的内存地址两次都是相同的。有人知道这是为什么吗?在我能够理解这个装饰器/闭包魔法之前,我还有一段路要走。

我找到了一个包装器,它将写入函数名

from functools import wraps

def tmp_wrap(func):
    @wraps(func)
    def tmp(*args, **kwargs):
        print func.__name__
        return func(*args, **kwargs)
    return tmp

@tmp_wrap
def my_funky_name():
    print "STUB"

my_funky_name()

这将打印

my_funky_name 存根