Correction to the correction. This will
converge, eventually.
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Nick Cox
> Sent: 18 March 2004 11:58
> To: [email protected]
> Subject: RE: st: dropping variables
>
> Correction: the effect of Dimitry's loop
> 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/
>
*
* For searches and help try:
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* http://www.ats.ucla.edu/stat/stata/
