Defining default keyword values to function in a dictionary in python

Question

I am writing a function that takes a lot of keywords.

I have a dictionary which is very lengthy that contains many of these keywords that already exists in my code and is being used elsewhere. Eg

{'setting1':None, 'setting2': None....}

I am wondering is there a way, when I define my function, for me to set all of these as keywords, rather than having to type them out again like this:

def my_function(setting1=None, setting2=None, **kwargs)

To be clear, essentially I want to set all of the contents of the dictionary to be keywords with default value None, and when I call the function I should be able to change their values. So I am not looking to provide the dictionary as kwargs upon calling the function.

Answer 1

While not exactly the same, I ususally prefer to save the arguments in **kwargs and use .get() to get the value or None :

def my_function(**kwargs):
     do_something(kwargs.get("alpha"), kwargs.get("beta"))

.get() on a dictionary returns the value if a key exists, or None of it does not. You can optionally specify a different default value as a second argument if you like.

Answer 2

When creating a function, you will need to implement how your arguments are used. By automatically creating arguments you end up adding arguments and forgetting to implement a behaviour for them.

# Manually defined.
def func(a, b, c, d):
    return a + b / c * d

# Auto-defined - Human error.
def func(""" auto define a,b,c,d,e,f,g,h """):
    return a + b / c * d # <- you only use half of the arguments. Confusing at best.

# Auto-defined - Inputs unclear, code is not explicit.
def func(defind_my_args):
    return a + b / c * d 

If you need to reuse "code behaviour" to the point that you can "inherit" parameters, maybe you should be using an object instead.