What does the asterisk do in *a, b, c = line.split()?

Question

Assume line is: \"Chicago Sun 01:52\".

What does *a, b, c = line.split() do? In particular, what is the significance of the a

Answer 1

Splitting that text by whitespace will give you:

In [743]: line.split()
Out[743]: ['Chicago', 'Sun', '01:52']

Now, this is a 3 element list. The assignment will take the last two elements of the output and assign them to b and c respectively. The *, or the splat operator will then pass the remainder of that list to a, and so a is a list of elements. In this case, a is a single-element list.

In [744]: *a, b, c = line.split()

In [745]: a
Out[745]: ['Chicago']

In [746]: b
Out[746]: 'Sun'

In [747]: c
Out[747]: '01:52'

Look at PEP 3132 and Where are python's splat operators * and ** valid? for more information on the splat operators, how they work and where they're applicable.