python - Negative list index?

I'm
trying to understand the following piece of
code:

# node
            list

n = []
for i in xrange(1, numnodes + 1):

            tmp = session.newobject();
 n.append(tmp)
link(n[0],
            n[-1])

Specifically, I
don't understand what the index -1 refers to. If the index
0 refers to the first element, then what does
-1 refer to?

class="post-text" itemprop="text">

class="normal">Answer

Negative
numbers mean that you count from the right instead of the left. So,
list[-1] refers to the last element,
list[-2] is the second-last, and so
on.