How to count the number of non-duplicate values in a 1-column table?

[Anonymous]

I want to count the number of unique values in a column (excluding duplicates and values of duplicates). Here is a sample 1-column table:

ID

A

A

A

B

C

D

D

E

My ideal output is 3 (it includes 'B', 'C', 'E'). 'A' and 'D' are ignored since they have duplicates in the column.

[Greg_Deckler]

@Anonymous Try:

Measure =
  VAR __Table = ADDCOLUMNS('Table',"__Count",COUNTROWS('Table',[ID] = EARLIER([ID]))
RETURN
  COUNTROWS(FILTER(__Table, [__Count] = 1))

[Anonymous]

@Greg_Deckler 

Thanks for the suggestion. I am receiving an error that too many arguments were passed to the COUNTROWS function. Is there a way to work around this?

[Greg_Deckler · Accepted solution]

@Anonymous Yeah, I missed a FILTER:

Measure =
  VAR __Table = ADDCOLUMNS('Table',"__Count",COUNTROWS(FILTER('Table',[ID] = EARLIER([ID])))
RETURN
  COUNTROWS(FILTER(__Table, [__Count] = 1))