what is the purpose of the asterisk symbol in "complex(*(1,2))" in python without which it will return an error?

Question

I am learning about complex function in python.

I understand the input to the complex function complex(a, b) and will return a+ bi. What I don't understand is when I input in tuples form, complex((a, b)), it will return an error but if I use complex(*(a, b)) it will return a+ bi. so in this case, is the asterisk particularly part of complex function's argument when giving it as a tuple or is it performing some kind of operation? Thanks.

Answer 1

The *-operator is used for argument unpacking.

You're not calling the function in the same way. Think of it this way:

complex(real=a, imaginary=b)
# vs.
complex(real=(a, b))

This is also why you see people write def fn(*args, **kwargs), it means that all arguments and keyword arguments will be unpacked.