在python中将多个参数传递给init类的最佳方法是什么？

Question

I am creating a module in python that can take multiple arguments. What would be the best way to pass the arguments to the definition of a method?

def abc(arg):
    ...

abc({"host" : "10.1.0.100", "protocol" : "http"})

def abc(host, protocol):
    ...

abc("10.1.0.100", "http")

def abc(**kwargs):
    ...

abc(host = "10.1.0.100", protocol = "http")

Or something else?

Edit

I will actually have those arguments (username, password, protocol, host, password2) where none of them are required.

Answer 1

def abc(host, protocol):
    ...

abc("10.1.0.100", "http")
abc(host="10.1.0.100", protocol="http")

If you call it using positional args or keyword args depends on the number of arguments and if you skip any. For your example I don't see much use in calling the function with keyword args.

---

Now some reasons why the other solutions are bad:

abc({"host" : "10.1.0.100", "protocol" : "http"})

This is a workaround for keyword arguments commonly used in languages which lack real keyword args (usually JavaScript). In those languages it is nice, but in Python it is just wrong since you gain absolutely nothing from it. If you ever want to call the functions with args from a dict, you can always do abc(**{...}) anyway.

def abc(**kwargs):

People expect the function to accept lots of - maybe even arbitrary - arguments. Besides that, they don't see what arguments are possible/required and you'd have to write code to require certain arguments on your own.

Answer 2

If all the arguments are known ahead, use an explicit argument list, optionally with default values, like def abc(arg1="hello", arg2="world",...) . This will make the code most readable.

When you call the function, you can use either abd("hello", "world") or abc(arg1="hello", arg2="world") . I use the longer form if there are more than 4 or 5 arguments, it's a matter of taste.

Answer 3

This really depends on the context, the design and the purpose of your method.

If the parameters are defined and compulsory, then the best option is:

def abc(host, protocol):
    ...

abc('10.1.0.100', 'http')

in case the parameters are defined but optional, then:

def abc(host=None, protocol=None): # I used None, but put a default value
    ...

you can call it thorugh positional arguments as abc('10.1.0.100', 'http') or by their name abc(protocol='http')

And if you don't know at first what are the arguments it will receive are (for example in string formatting) then the best option is using the **kwargs argument:

def abc(**kwargs):
    ...

And in this way you must call it using named arguments.