# RE: st: count (Stata 8)

 From "Nick Cox" To Subject RE: st: count (Stata 8) Date Tue, 10 May 2005 22:16:10 +0100

```-egen- haters can spend a line interactively and
save dozens and dozens off-stage:

bysort year : gen cases = sum(dflag)
by year : replace cases = cases[_N]
by year: gen n = _N

Also, in Stata 9, -egen, sum()- still works but
the preferred name is now -total()-.

Nick
n.j.cox@durham.ac.uk

Heather Gold

> Thanks - this works perfectly to give both scalars and variables. I
> At 03:02 PM 5/10/2005, you wrote:
> >I'm on record as a big fan of -foreach- but this problem
> >doesn't seem to need a loop at all.
> >
> >Nevertheless, you want scalars, although I am not clear why.
> >
> >You can have it both ways by having variables and scalars too.
> >(The variables will come in useful for graphs and tables.)
> >
> >egen cases = sum(dflag), by(year)
> >egen n = sum(1), by(year)
> >gen prevalence = cases / n
> >tabdisp year, c(prevalence)
> >
> >levelsof year, local(Y)
> >foreach y of local Y {
> >         su prev if year == `y', meanonly
> >         scalar prev`y' = r(min)
> >}

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```