The Problem of COUNTIF in Apple Numbers
If you have a list of values in a column, where duplicates exists, and you want to extract unique values dynamically, using a regular spreadsheet, (the open sourced one, or the popular one) you could use COUNTIF. You would just compare the column with the values, with the column with the extracted values.
So for example: A formula like =INDEX($C$5:$C$11,MATCH(0,INDEX(COUNTIF($D$4:D4,$C$5:$C$11),0,0),0))
in the column D, filled down, and using values on column C will result in:
You can do that because the output of COUNTIF in the rest of the software in the market IS AN ARRAY. So you can MATCH your results inside the same cell. However, the output of COUNTIF in Numbers is a number. So you cant MATCH. And even when numbers does not support formula arrays, IT DOES support arrays as input of certain functions, and as output of some others, so it's a little unclear why Apple decided to limit COUNTIF in this way.
Understanding that, the question would be: Is there a way to do this same thing in numbers?... and i'm not talking about a workaround using several columns. I'm talking about a way of fill down cells with a formula, obtaining the unique values dynamically. Since i spent 3 days trying to do that, and i couldn't, maybe there isn't. If not, wouldn't be awesome if COUNTIF in Numbers catch up the rest of the software out there??