How to get a function name as a string?

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How do I get a function's name as a string?

def foo():
    pass

>>> name_of(foo)
"foo"
14 Answers
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.

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. :)

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"
import inspect

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

where

  • stack()[0] is the caller

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

I've seen a few answers that utilized decorators, though I felt a few were a bit verbose. Here's something I use for logging function names as well as their respective input and output values. I've adapted it here to just print the info rather than creating a log file and adapted it to apply to the OP specific example.

def debug(func=None):
    def wrapper(*args, **kwargs):
        try:
            function_name = func.__func__.__qualname__
        except:
            function_name = func.__qualname__
        return func(*args, **kwargs, function_name=function_name)
    return wrapper

@debug
def my_function(**kwargs):
    print(kwargs)

my_function()

Output:

{'function_name': 'my_function'}
import inspect

def my_first_function():
    func_name = inspect.stack()[0][3]
    print(func_name)  # my_first_function

or:

import sys

def my_second_function():
    func_name = sys._getframe().f_code.co_name
    print(func_name)  # my_second_function

You can get a function's name as a string by using the special __name__ variable.

def my_function():
    pass

print(my_function.__name__) # prints "my_function"
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