How to find unique and common words per line from a txt file?

[Gribouillis]

You can make this a little shorter

odds, even = eo = [set(), set()]
with open('shakespeare.txt') as f:
    for index, row in enumerate(f):
        eo[index % 2].update(row.strip().split())

Observe that python numbers lines from 0 while common CS and programming literature and software starts line counts at 1.