How to get a function name as a string in Python?


Question

In Python, how do I get a function name as a string, without calling the function?

def my_function():
    pass

print get_function_name_as_string(my_function) # my_function is not in quotes

should output "my_function".

Is such function available in Python? If not, any ideas on how to implement get_function_name_as_string, in Python?

1
641
12/5/2018 7:13:20 AM

Accepted Answer

my_function.__name__

Using __name__ is the preferred method as it applies uniformly. Unlike func_name, it works on built-in functions as well:

>>> import time
>>> time.time.func_name
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
AttributeError: 'builtin_function_or_method' object has no attribute 'func_name'
>>> time.time.__name__ 
'time'

Also the double underscores indicate to the reader this is a special attribute. As a bonus, classes and modules have a __name__ attribute too, so you only have remember one special name.

808
11/1/2008 12:07:17 AM

To get the current function's or method's name from inside it, consider:

import inspect

this_function_name = inspect.currentframe().f_code.co_name

sys._getframe also works instead of inspect.currentframe although the latter avoids accessing a private function.

To get the calling function's name instead, consider f_back as in inspect.currentframe().f_back.f_code.co_name.


If also using mypy, it can complain that:

error: Item "None" of "Optional[FrameType]" has no attribute "f_code"

To suppress the above error, consider:

import inspect
import types
from typing import cast

this_function_name = cast(types.FrameType, inspect.currentframe()).f_code.co_name

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