python条件类型转换

Question

I'm trying to make sure user arguments are of a certain type, when run script run from cmd line with -> python Script.py argv1 argv2 argv3 etc...

The idea is that if the user only enters say 2 cmd line arguments, the rest of the variables in arg_list will default. I want to make sure that the ones they did enter were of the right type.

Below is a mock up of the situation I have. At the moment when the if condition fails it's not picked up by the except block (is there a way around this??) In reality there's a lot more variables so putting a try-except for each if clause isn't practical.

arg1 = 3.14
arg2 = "Default 1"
arg3 = "Default 2"
arg4 = True
arg_list = [arg1, arg2, arg3, arg4]

for i in range(1, len(sys.argv)):

    try:
        if i==1:
            arg_list[i-1] = float(sys.argv[i])
        elif i==2 or i==3:
            arg_list[i-1] = str(sys.argv[i])
        else i==4:
            arg_list[i-1] = bool(sys.argv[i])

    except TypeError as e:
        # do stuff

Any help would be great, thanks!

Answer 1

typelist = [float, str, str, bool]

for i, item in enumerate(sys.argv[1:]):
    assert type(item) == typelist[i]