How to get a function name as a string?

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         


        

Answer 1

I like using a function decorator. I added a class, which also times the function time. Assume gLog is a standard python logger:

class EnterExitLog():
    def __init__(self, funcName):
        self.funcName = funcName

    def __enter__(self):
        gLog.debug('Started: %s' % self.funcName)
        self.init_time = datetime.datetime.now()
        return self

    def __exit__(self, type, value, tb):
        gLog.debug('Finished: %s in: %s seconds' % (self.funcName, datetime.datetime.now() - self.init_time))

def func_timer_decorator(func):
    def func_wrapper(*args, **kwargs):
        with EnterExitLog(func.__name__):
            return func(*args, **kwargs)

    return func_wrapper

so now all you have to do with your function is decorate it and voila

@func_timer_decorator
def my_func():

Answer 2

my_function.func_name

There are also other fun properties of functions. Type dir(func_name) to list them. func_name.func_code.co_code is the compiled function, stored as a string.

import dis
dis.dis(my_function)

will display the code in almost human readable format. :)

Answer 3

import inspect

def foo():
   print(inspect.stack()[0][3])

where

• stack()[0] is the caller

• stack()[3] is the string name of the method

Answer 4

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.

Answer 5

If you're interested in class methods too, Python 3.3+ has __qualname__ in addition to __name__.

def my_function():
    pass

class MyClass(object):
    def method(self):
        pass

print(my_function.__name__)         # gives "my_function"
print(MyClass.method.__name__)      # gives "method"

print(my_function.__qualname__)     # gives "my_function"
print(MyClass.method.__qualname__)  # gives "MyClass.method"

Answer 6

Try

import sys
fn_name = sys._getframe().f_code.co_name

further reference https://www.oreilly.com/library/view/python-cookbook/0596001673/ch14s08.html