Why do python list with a single entry give the 0th element for -1 index and 0 index?

Question

On creating a list in python with just one element, when I try to get the -1 index element instead of getting list index out range error it is giving the 0th element.

some = ['something']
print(some[0]) # prints something
print(some[-1]) # prints something

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Answer 1

A negative index means nth from the right. The zero-index of a one-element list is the same as the negative-one-index of a one-element list because the zeroth element is the same as the first element from the right.