Getting Function Names as Strings in Python

In Python, functions are first-class citizens, which means they can be treated like any other object. This includes accessing their names as strings. In this tutorial, we will explore how to get a function’s name as a string using various methods.

Using the __name__ Attribute

The most straightforward way to get a function’s name is by accessing its __name__ attribute. This attribute returns the name of the function as a string.

def my_function():
    pass

print(my_function.__name__)  # Output: "my_function"

This method works uniformly for all types of functions, including built-in functions and methods.

Getting the Current Function’s Name

To get the current function’s name from inside it, you can use the inspect module. Specifically, you can access the f_code.co_name attribute of the current frame.

import inspect

def my_function():
    this_function_name = inspect.currentframe().f_code.co_name
    print(this_function_name)  # Output: "my_function"

my_function()

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

Getting the Calling Function’s Name

If you want to get the calling function’s name instead, you can use the f_back attribute of the current frame.

import inspect

def my_function():
    this_function_name = inspect.currentframe().f_code.co_name
    print(this_function_name)  # Output: "my_function"

def caller_function():
    my_function()

caller_function()

To get the calling function’s name, you can modify the code as follows:

import inspect

def my_function():
    calling_function_name = inspect.currentframe().f_back.f_code.co_name
    print(calling_function_name)  # Output: "caller_function"

def caller_function():
    my_function()

caller_function()

Using __qualname__ for Class Methods

In Python 3.3 and later, you can use the __qualname__ attribute to get the qualified name of a function or method.

class MyClass:
    def my_method(self):
        pass

print(MyClass.my_method.__name__)         # Output: "my_method"
print(MyClass.my_method.__qualname__)     # Output: "MyClass.my_method"

Best Practices and Tips

• Always use the __name__ attribute to get a function’s name, as it is the most straightforward and uniform method.
• Use the inspect module to get the current or calling function’s name when needed.
• Be aware of the differences between __name__ and __qualname__ attributes, especially when working with class methods.

By following these guidelines and using the provided code examples, you should be able to effectively work with function names as strings in Python.