Define a function with dynamic arguments, keyword arguments from user and print them

Question

Code:

def myFun(*args, **kwargs):
    print("args: ", args)
    print("kwargs: ", kwargs)
args = input("Enter args: ")
kwargs = input("Enter kwargs: ")
myFun(args,kwargs)

Output:

Enter args: 1,2,3,4
Enter kwargs: a=5,b=6,c=7
args:  ('1,2,3,4', 'a=5,b=6,c=7')
kwargs:  {}

Process finished with exit code 0

Here the expected output is:

args: (1,2,3,4)

kwargs: {'a':5,'b':6,'c':7}

I am getting the output not as the expected output.

Why are you expecting that output? You're not doing anything with the user input - no [splitting on commas](https://stackoverflow.com/q/5864485/4518341), no [converting the `kwargs` string to a dict](https://stackoverflow.com/q/12739911/4518341), and no [converting strings to ints](https://stackoverflow.com/q/7368789/4518341). — wjandrea, Jun 28 '20 at 05:23

Xinthral · Answer 1 · 2020-06-28T06:06:14.457

1

So there are a few things here to note, you args are coming out as strings because they are being passed as strings. kwargs and args are variable names, but *args and **kwargs are not. So what you're trying to do is probably something like:

def parseArgs(inputString):
    return(inputString.split(','))
def parseKWargs(inputString):
    d = {}
    for element in parseArgs(inputString):
        current = element.split('=')
        d[current[0]] = current[1]
    return(d)
def myFun(*args, **kwargs):
    print("args: ", args)
    print("kwargs: ", kwargs)
args = parseArgs(input("Enter args: "))
kwargs = parseKWargs(input("Enter kwargs: "))

myFun(*args, **kwargs)

kwargs needs to be a dictionary and "passed by reference" I believe is the correct way to word that. Hope this helps.

Thanks wjandrea for the good catches

edited Jun 28 '20 at 06:06

answered Jun 28 '20 at 05:24

Xinthral

438
2
10

1

Check the output. This isn't quite correct. I'm getting `args: (['1', '2', '3', '4'],)` and `kwargs: {'a': '5', 'b': '6', 'c': '7'}` – wjandrea Jun 28 '20 at 05:28
1

BTW, don't use `input` as a variable name cause it shadows the builtin `input()`. Also `argparse` is the name of a standard library module, so you may want to use a different name to avoid confusion, but nbd. – wjandrea Jun 28 '20 at 05:31
@wjandrea is absolutely correct, using input is a bad practice; only meant for demonstrative purposes, and I will update the example to return multiple arguments instead of an argument list momentarily. – Xinthral Jun 28 '20 at 06:01

Leo Arad · Accepted Answer · 2020-06-28T07:05:15.557

1

You can use list and dictionary comprehension to parse the input of the users to be list to args and dictionary to kwargs and then unpacked them into myFun.

def myFun(*args, **kwargs):
    print("args: ", args)
    print("kwargs: ", kwargs)

args = [int(i) if i.isdigit() else i for i in input("Enter args: ").split(",")]
kwargs = {i.strip().split("=")[0]: int(i.strip().split("=")[1]) if i.strip().split("=")[1].isdigit() else i.strip().split("=")[1] for i in input("Enter kwargs: ").split(",")}

myFun(*args, **kwargs)

Entered

Enter args: 1,2,3,4
Enter kwargs: a=5,b=6,c=7

Output

args:  (1, 2, 3, 4)
kwargs:  {'a': 5, 'b': 6, 'c': 7}

edited Jun 28 '20 at 07:05

answered Jun 28 '20 at 06:30

Leo Arad

4,452
2
6
17

The value in the dictionary should be int not str. – Ketha Jun 28 '20 at 06:54
Edited the code to convert numbers to int in the dictionary. – Leo Arad Jun 28 '20 at 06:59

Define a function with dynamic arguments, keyword arguments from user and print them

2 Answers2