Is there a way to check a function's signature in Python?

Question

I\'m looking for a way to check the number of arguments that a given function takes in Python. The purpose is to achieve a more robust method of patching my classes for tests.

Answer 1

You should use inspect.getargspec.

Answer 2

inspect.getargspec is deprecated in Python 3. Consider something like:

import inspect
len(inspect.signature(foo_func).parameters)

Answer 3

The inspect module allows you to examine a function's arguments. This has been asked a few times on Stack Overflow; try searching for some of those answers. For example:

Getting method parameter names in python

Answer 4

You can use:

import inspect
len(inspect.getargspec(foo_func)[0])

This won't acknowledge variable-length parameters, like:

def foo(a, b, *args, **kwargs):
    pass