Exam 70-779 topic 1 question 58 discussion

The 1 is the second argument of the COUNTX function and represents the element to be counted. I think Users[UserID] would be more appropriate and easier to understand. But because we are just counting the results of the FILTER function it doesn't matter so a simple 1 will do the trick.

COUNTX(<table>,<expression>)  Counts the number of rows that contain a non-blank value or an expression that evaluates to a non-blank value, when evaluating an expression over a table. FILTER(<table>,<filter>)  Returns a table that represents a subset of another table or expression. Regarding the “1”, go with “Zandt” in discussion, better input is “Users[UserID]” which what we need to count. Example 2 The following formula illustrates how to pass a filtered table to COUNTX for the first argument. The formula uses a filter expression to get only the rows in the Product table that meet the condition, ProductSubCategory = "Caps", and then counts the rows in the resulting table that have a list price. The FILTER expression applies to the table Products but uses a value that you look up in the related table, ProductSubCategory. DAXCopy = COUNTX(FILTER(Product,RELATED(ProductSubcategory[EnglishProductSubcategoryName])="Caps"), Product[ListPrice])

I tested it and it works ok with COUNTX and Filter. I tested with COUNT and it gives me an error.

Countx function can only have two arguments, and here we have 3?!

What does this 1 stand for?