Re: st: RE: Changing positive values to negative in Stata

[Suzy <scott_788@wowway.com>]

Dear Martin,

Your code worked perfectly well  for my data... Thanks!!  Thanks also to 
Nick!

replace suzy = -suzy if suzy  > 0 & ( scott > 0 & scott < 103)  (the max 
value was 102.27272)


Maarten buis wrote:


> Lets call this other variable which captures the common charecteristics scott, and suzy has to be
> negative if scott is larger than 2 and less than pi or is equal to e to the power pi. Than you
> would code:
>
> replace suzy = -suzy if suzy > 0 & ( scott > 2 & scott < c(pi) ) | scott == exp(1)^c(pi)
>
> --- Suzy <scott_788@wowway.com> wrote:
>
>  
>
> > Thanks Nick - I neglected to state that  have over 600 observations with 
> > all different positive values (as well as negative values and missing 
> > values) within the subgroup of total observations of the variable, so 
> > this code could be somewhat inefficient.  Also,  it is difficult to 
> > specify which observations, for example, by id  - thus  the next best 
> > thing in this instance seems to be to sort by their common 
> > characteristic - which  is captured by another variable.
> >
> > Nick Cox wrote:
> >
> >    
> >
> > > replace suzy = -suzy if suzy > 0 & <whatever> 
> > > So if suzy is positive, it is negated. The 
> > > crunch is specifying the extra condition <whatever> 
> > > that catches just the observations desired. 
> > > Sorting is a red herring here. So long as you 
> > > can specify which observations you want, sort order
> > > is immaterial. 
> > > Nick 
> > > n.j.cox@durham.ac.uk 
> > > Suzy
> > >
> > >
> > >
> > >      
> > >
> > > > I have a continuous variable with positive, negative, and zero values 
> > > > and also missing values(.). 
> > > > I would like to know if anyone has an easy Stata code/command 
> > > > to change 
> > > > just the positive values to a negative (change the sign: 4.4567 to 
> > > > -4.4567) for just a particular subgroup of the total (n=661 
> > > > out of over 
> > > > N=4,000). Within this subgroup (which I can sort, but not by 
> > > > id) there 
> > > > already are a few appropriately negative values in place.
> > > >   
> > > >        
> > > *
> > > *   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/
> >
> >    
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> visiting adress:
> Buitenveldertselaan 3 (Metropolitan), room Z214
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
> 		
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> *
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>
>
>
>  

*
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