is to -drop- all string variables,
as r(N) is returned as 0.
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Nick Cox
> Sent: 18 March 2004 11:50
> To: [email protected]
> Subject: RE: st: dropping variables
>
>
> A problem with Dimitry's loop is that it will crash
> the first time it hits a string variable. I would
> tune it to
>
> foreach v of var * {
> qui count if !missing(`v')
> if r(N) < 100 drop `v'
> }
>
> where 100 is of course a place-holder for your own
> desired constant.
>
> -count- remains an under-appreciated command.
>
> Nick
> [email protected]
>
> Dimitriy V. Masterov
>
> > There might be a more clever way of doing this, but here's my
> > solution:
> >
> > /* This defines a local named variables that contains a list
> > with all variables */
> > unab variables: _all
> >
> > /* This loop drops all variables that have fewer than 100 obs. */
> > foreach var in `variables' {
> > qui sum `var'
> > if r(N)<100 {
> > drop `var'
> > }
> > }
>
> Eric Uslaner
>
> > > I know of Nick Cox's great dropmiss program. I want to
> do something
> > > akin to it (without having to drop each variable
> individually). Say
> > > that a data set has N cases and I want to drop variables
> > that have fewer
> > > than n nonmissing cases. Theoretically I could generate
> > new variables
> > > through count, but my data set is already close to the
> > maximum allowed
> > > without upgrading to SE (which is why I want to drop some
> > variables).
> > > Is there a way to do this:
> > >
> > > drop if _N < n
> > >
> > > or something similar?
>
> *
> * For searches and help try:
> * http://www.stata.com/support/faqs/res/findit.html
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
