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Re: st: append to an empty dataset


From   Johannes Geyer <JGeyer@diw.de>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: append to an empty dataset
Date   Tue, 4 Nov 2008 15:05:07 +0100

I had/have that problem too and most often I have to create a cycle and an 
exception (the first data set). Reading throught your posts I thought why 
not add that option -gen tempvar- to append when using it?

Wouldn't that suffice?:

**************
program append_empty
syntax using [, *]

tempvar qwerty 
gen `qwerty' = 1

append `using', `options'
end
**************

**************
clear
append_empty somedataset
**************

Johannes


----------------------
Johannes Geyer
Deutsches Institut für Wirtschaftsforschung (DIW Berlin)
German Institute for Economic Research 
Department of Public Economics
DIW Berlin
Mohrenstraße 58
10117 Berlin
Tel: +49-30-89789-258

owner-statalist@hsphsun2.harvard.edu schrieb am 03/11/2008 22:07:30:

> I'll back this request, too. I use -append- to combine my simulated
> files, and what I do is I create a -postfile- without actually
> -post-ing anything in it, so it comes out with zero observations and
> all the variable names needed. Something like that was done by Phil
> Schumm & co (am I attributing this right?) a few years back when they
> were setting up questionnaires and other survey-related
> characteristics of the data in the -notes- section of the file with
> zero observations, to be filled up later at actual the data collection
> stage. But I do think that -append-ing to the empty data set should be
> a reasonable thing to do.
> 
> On 11/3/08, Jeph Herrin <junk@spandrel.net> wrote:
> >
> >  Sergiy,
> >
> >  I posted this same question two years ago:
> >
> > http://www.stata.com/statalist/archive/2006-07/msg00097.html
> >
> >  and received no satisfactory response. I often have the
> >  same problem you have, and proposed that -append- have an
> >  -empty- option, for instance, so that I can force it to
> >  use the file if there is nothing in memory. I guess it will
> >  have to go on a wishlist for StataCorp.
> >
> >  cheers,
> >  Jeph
> >
> >
> >
> >  Sergiy Radyakin wrote:
> >
> > > Dear all,
> > >
> > > is there any reason for -append- to refuse to run when there is no
> > > data in memory?
> > >
> > > clear
> > > append using something.dta
> > >
> > > I often have a list of files to combine, and go with a simple loop,
> > > but when none of them is in memory, I have to brunch the program to
> > > specially treat the first file in the list, which is annoying. Since
> > > -append- is built-in, I can't look into what it is doing or needing.
> > > Otherwise I wish -append- worked as -use- when there is no data in
> > > memory. So that the below code could work.
> > >
> > > local bunch_of_files "alpha beta gamma delta"
> > > clear
> > > foreach file of local bunch_of_files {
> > >  append using `"`file'"', nolabel
> > > }
> > >
> > > Notably it is not the observations that -append- requires, but
> > > variables, e.g. the following works:
> > >
> > > local bunch_of_files "alpha beta gamma delta"
> > > clear
> > > generate byte __STRANGE_VAR_NAME=1 /* still zero observations here 
*/
> > > foreach file of local bunch_of_files {
> > >  append using `"`file'"', nolabel
> > > }
> > > drop __STRANGE_VAR_NAME
> > >
> > > Thank you, Sergiy Radyakin
> > > *
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> > >
> > >
> >  *
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> >
> 
> 
> -- 
> Stas Kolenikov, also found at http://stas.kolenikov.name
> Small print: I use this email account for mailing lists only.
> *
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