count distinct values in spreadsheet

Question

I have a Google spreadsheet with a column that looks like this:

City
----
London
Paris
London
Berlin
Rome
Paris

I want to count the appeara

Answer 1

Not exactly what the user asked, but an easy way to just count unique values:

Google introduced a new function to count unique values in just one step, and you can use this as an input for other formulas:

=COUNTUNIQUE(A1:B10)