pandas provides methods that allow us to clearly state how we want to index. We can also distinguish between indexing based on values of the index of the series, and indexing based on the position of objects in the series, as would be the case if we were working with a list. The two methods we'll focus on are loc and iloc. loc focuses on selecting based on the index of the series, and if we try to select key elements that don't exist, we will get an error. iloc indexes as if we were working with a Python list; that is, it indexes based on integer position. So, if we were to try to index with a non-integer in iloc, or try to select an element outside of the range of valid integers, an error will be produced. There is a hybrid method, ix, that acts like loc, but if passed input that cannot be interpreted with respect to the index, it will act like iloc. Because of the ambiguity about how ix will behave, I recommend sticking with loc or iloc most of the time.
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