On Fri, 29 Dec 2006, sj wrote:
> I am working with a dataset where there are 5 possible outcomes (coded 1:5),
> I would like to create 5 categorical variables (event1...event5). I am using
> a for loop an if statements, but I have a large dataset( approx 100,000
> rows) it takes quite a bit of time, is there a way to speed this up? Here is
> some sample code of what I am currently doing.
>
> test2 <-rep(seq(1:5),2000)
>
[...]
As Richard suggested you may not want to do this at all, but ...
If you want these as a matrix, this is fast and direct:
mat <- diag(5)[ test2, ]
If not as a matrix
event1 <- as.numeric( test2 == 1 )
is concise and
for (i in 1:5) assign(paste("event",i,sep=""), as.numeric( test2==i ))
is about as fast as you can get.
HTH,
Chuck
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:[EMAIL PROTECTED] UC San Diego
http://biostat.ucsd.edu/~cberry/ La Jolla, San Diego 92093-0717
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