In Python 3.x, map()
returns an iterable, not a list. If you want a list, use list(map(...))
.
The normal use case is just to iterate over it, which you can do just as you would if it was a list.
Arguably a better solution here is a list comprehension:
[x / 20 for x in self.damage]
As a note, dividing by 20 is not a 20% reduction (it's a 95% reduction) - to do that, you want:
[x * 0.8 for x in self.damage]