Counting the # of factors when using "i.index"

[Sukhun Kang]

I am running ols with individual fixed effects and year fixed effects by including "i.index" and "i.year". I cannot use xtreg because I need to use 'iweight' option.

Is there a way to compute # of index that were included in the regression? I have more than 9,000 individuals thus manually counting is not feasible.

[Joseph Coveney]

Maybe something along these lines

sysuse auto
regress headroom i.rep78

*
* Begin here
*
preserve
quietly keep if e(sample)
contract rep78
count
restore