[R] vectorising ifelse()

Federico Calboli f.calboli at imperial.ac.uk
Fri Jul 22 23:57:10 CEST 2005

On 22 Jul 2005, at 11:20, Adaikalavan Ramasamy wrote:

> Does either 'zippo' or 'zappo' contain the values 1 or 2 ?
> If so, then you cannot vectorize this code because you are changing  
> the
> values in 'new' at every iteration and potentially sampling a value  
> from
> new[ ,1] or new[ ,2] .

That's exactly my situation, and is exactly what I want to do.

After taking out the typo (and bug) "drow[i]>0" the code seems to  
work fast enough... I'll tinker a bit with it, but it could be good  
enough as it is.


Federico Calboli

Federico C. F. Calboli
Department of Epidemiology and Public Health
Imperial College, St. Mary's Campus
Norfolk Place, London W2 1PG

Tel +44 (0)20 75941602   Fax +44 (0)20 75943193

f.calboli [.a.t] imperial.ac.uk
f.calboli [.a.t] gmail.com

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