Why difference in calculation results with or without Dollar-sign expansion?

[MeehyeOh]

Hi, 

I created an expression using the "AddMonths" and "MonthName" functions to calculate yearmonth about 2 months ago.

However, the same expression comes out differently depending on whether or not the Dollar-sign expansion.

The difference is the format of the value returned.

(**In the image below, the KPI chart is set the same number formatting : "Auto"**)

Expression without Dollar-sign expansion : Numeric

Expression with Dollar-sign expansion : Date

Why are the results different?

[marcus_sommer · Accepted solution]

Monthname() returned a dual() with a formatted date in the string-part and a number. The $-sign expansion is an adhoc variable and variables aren't dual else they contain always the string representation which means in your case it's only a string which looked like a date.

[MeehyeOh]

Hi @marcus_sommer 

Thank you for reply.

You mean when calculating a dual value return function through a  $-sign expansion, I always get a string value?

[marcus_sommer]

Yes, a variable contained always a string - which might be interpreted as string or as number depending on the used context but never be a dual().