### Title

Summary count of duplicate numbers..

### Post

I have a layout report that shows a list of N Numbers. Many of these are duplicates (which is normal). They are sorted in N Number order, so the duplicates are together. I want to know the total number of unique N Numbers there are. In other words I want a count of the groups of N Numbers, not how many are in each group.

Example: If my list looked like this:

N123

N123

N567

N678

N999

N999

N999

The summary count I would want to see is: 4

The value list method also seems pretty slick, basing a value list on the field and thus stripping duplicates as a side effect. Then counting the value list items.

For some reason I have an inherent dislike of using side effects, but have no defensible stance on it. It shows a great understanding of FMP's quirks and how to use them to advantage.