How to format a variable in Stata? - stata

Question

I am trying to grab the formatted current data and create a variable from it using the command:
gen %tdCY-N-D final_dayinpt = date(c(current_date), "DMY")
However, I am getting an error
%tdCY invalid name
r(198);
If I display this at the Stata command line it works:
. display %tdCY-N-D date(c(current_date), "DMY")
2020-10-27
How can I create this formatted variable?

Answer 1

Solution:
set obs 10 // so the example works
generate final_dayinpt = date(c(current_date), "DMY")
format final_dayinpt %tdCY-N-D
The syntax you're trying is tempting because the format you use for display is seems analogous to things like generate byte bytevar = 1, but, as you found the analogy doesn't hold here.
Note that you are passing format information where type is expected based on the generate syntax (help generate):
generate [type] newvar[:lblname] =exp [if] [in] [, before(varname) | after(varname)]
While consulting help generate and help display are helpful, help datetime is also very useful here (and was never obvious to me).
See here for a more thorough treatment of working with dates in Stata.
Edit:
An alternative suggested (and made possible by) Nick Cox:
ssc install numdate // install the package which Nick wrote
generate current_date = c(current_date) // numdate takes a varlist
numdate daily final_dayinpt = current_date, pattern(DMY) format(%tdCY-N-D)