Any way to find all possible kwargs for a function in python from cli?

Question

Is there a way to discover the potential keyword arguments for a function in python from the command line? without looking at the source or docs. Sometimes the source is to c lib even that isn't visible

Publishing

help(whatever_function)? – Fornof

By definition every possible key value pair is a potential keyword argument if you use kwargs – Murk

Answer 1

You can use the inspect module. In 3.3+, this is easy by using inspect.signature

import inspect

def foo(bar=None, baz=None):
    pass

>>> print(inspect.signature(foo))
(bar=None, baz=None)

Immediately underneath the linked doc is an example that pulls out only the names of the keyword-only arguments, which may be worth reading too!

Of course if you're looking to deep inspect the source code to try and find anything that is pulled out of a **kwargs argument, you're probably out of luck. Something like:

def foo(**kwargs):
    if kwargs.get("isawesome"):
        print("Dang you're awesome")

>>> some_magic(foo)
isawesome

is probably going to be hard to find.

Seema

Note also that this won't work for all builtin functions written in C, which don't usually have named arguments at all: E.g., try inspect.signature(sum) and you'll get an error. – Shire

A good point! I don't know if there's any way to inspect the signature of a function that's not written in Python. – Seema

Answer 2

For a function 'myfunc' use this:

myfunc.__code__.co_varnames

Seidel