Hello,
I have recently come across a use full equation that I use, however I am
perplexed about why it works. I am hoping someone can give me a clear
explanation, here it is:

{=sum(1/(countif(data,data))}

This is an array formula, used to count the distinct entries in a data set -
I know it works I just don't know why, and I have reduced it to subsets of
the equation but that just confused me more.

Thx, C