Last week in comp sci

We worked on arrays and gradually got more and more complex as we went. We also took a quiz, but I did not do very well because several of the concepts are still a bit confusing to me. The main one which I do not understand is the idea of the array shortcuts. I know that one can quickly make some kind of array creator by using two variables and a : but I do not understand exactly how this works and how it can be used in the context of other code. Otherwise all is well and I will simply have to review to move on.