函数参数打包和解包Python

Question

Currently, I have a function like so:

def my_func(*args):
    #prints amount of arguments
    print(len(args))
    #prints each argument
    for arg in args:
        print(arg)

I want to put multiple arguments through to this function, but the following doesn't work for me. It gives out a syntax error on the asterisk * after the else.

my_func(
    *(1, 2, 3, 4)
    if someBool is True
    else *(1, 2)
)

The workaround I found puts 1 and 2 in first and then puts 3 and 4 while checking for someBool.

my_func(
    1, 2,
    3 if someBool is True else None,
    4 if someBool is True else None
)

I am fine with the above as my function checks for None but if there is an alternative I would gladly thank them.

Answer 1

Move the * to outside the ... if ... else ... :

my_func(
    *((1, 2, 3, 4)
      if someBool is True
      else (1, 2))
)

Answer 2

You need an extra set of parenthesis. Also, you don't need to say is True to check if a Boolean is "truthy" in python, making it: my_func(*((1, 2, 3, 4) if someBool else (1, 2))) .