Excel Video 370 has an array formula that tells you if your list isn’t sorted. The trick is to know that Excel treats B as being greater than A, so our array formula will catch times when A comes after B in a sorted list. Remember the AND function is true if all of the arguments in the function are true. Our formula will be false if the data isn’t sorted in alphabetical order.
Adding the IF function to the AND formula allows us to display a warning message when the data isn’t sorted and to leave the cell blank when the data is sorted. It’s a clever way to track lists that you expected to be sorted. Thanks to Chandoo.org for the idea for this video and the next. The next array trick is to tell if a list is unique. We’ll work through that example next time.