I want to count the number of different text values in an unsorted column.
EXAMPLE:
I have a variety of text values in column 'A', for instance the 'city' value
of a persons address. And I have 5000 rows of data in the spreadsheet,
random people from all over the country.
I want to know how many different cities are represented by the random group
of people.

Is there a way to "COUNT" an array but count each unique value only once.