Python: How to avoid exec()?

Question

I have written the following function:

def get_id(arg_a: int, arg_b: int, arg_c: int, arg_d: int) -> str:
    '''Construct some example id for stackoverflow.'''
    if isinstance(arg_a, float):
        arg_a = int(arg_a)
    if isinstance(arg_b, float):
        arg_b = int(arg_b)
    if isinstance(arg_c, float):
        arg_c = int(arg_c)
    if isinstance(arg_d, float):
        arg_d = int(arg_d)
    return f'{arg_a}|{arg_b}|{arg_c}|{arg_d}'

When I started to refactor my program, I found this function to be written not in as much pythonic way as I would like, so I started to think, how to rewrite it. I found out, I could use exec() in combination with get_id.__code__.co_varnames, which will provide a tuple with function arguments to iterate over:

def get_id(arg_a: int, arg_b: int, arg_c: int, arg_d: int) -> str:
    '''Construct some example id for stackoverflow.'''
    for arg in get_id.__code__.co_varnames:
        exec(f'{arg} = int({arg}) if isinstance({arg}, float) else {arg}')
    return f'{arg_a}|{arg_b}|{arg_c}|{arg_d}'

But after that, I found out that exec() function is not suggested to be used in production programs from many reasons, which I understand. But I do not know, what to use instead of exec(). Please, could you help me, how to write my function in more general way and without exec() function?

Thanks for your help.

I see there are three answers already, but I still think that it is worth asking why you thought that exec was needed here in the first place. If you literally just remove it, and the f string inside it, you can just RUN what you are currently EXECing. Why did you think you needed to use exec? What were you stuck on that required that? — Neil
– Neil, Commented Dec 13, 2019 at 9:43

deceze · Accepted Answer · 2019-12-13 09:44:31Z

2

The most straight forward way is this:

def get_id(*args: int) -> str:
    return '|'.join(map(str, map(int, args)))

Nothing happens if you put an int through int(), so you can apply it to floats and ints alike.

If you want to list your parameters explicitly one by one:

def get_id(arg_a: int, arg_b: int, arg_c: int, arg_d: int) -> str:
    return '|'.join(map(str, map(int, (arg_a, arg_b, arg_c, arg_d))))

edited Dec 13, 2019 at 9:44

answered Dec 13, 2019 at 9:40

deceze♦

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