[R] Combining series of variables using identifier

[Henrique Dallazuanna]

Try this:

foo <- function(data, ...)
{
patt <- grep("var[0-9]$", names(data), value=T)
res <- paste(sapply(data[, patt], as.character), sapply(data[,
paste(patt, "lab", sep="_")], as.character), sep=": ")
cbind(a, matrix(res, ncol=length(patt), dimnames=list(NULL,
paste(patt, "new", sep="_"))))
}

foo(a)

On 26/02/2008, Lauri Nikkinen <lauri.nikkinen at iki.fi> wrote:
> R users,
>
>  I have df like this
>
>  a <- data.frame(    indx =    1:20,
>                     var1 =    rep(c("I20", "I40", "A50", "B60"), each=5),
>                     var1_lab= rep(c("cat", "dog", "mouse", "horse"), each=5),
>                     var2 =    rep(c("B20", "X40", "D50", "G60"), each=5),
>                     var2_lab= rep(c("car", "bicycle", "train", "bus"), each=5))
>  str(a)
>
>  I'd like to create new variables by combining "varX" and "varX_lab" like this:
>
>  a$var1_new <- factor(paste(a$var1, a$var1_lab, sep=": "))
>  a$var2_new <- factor(paste(a$var2, a$var2_lab, sep=": "))
>  a
>
>  But, in the real world, I have multiple df:s and many of variables
>  named by the same manner. Is there a possibility to create a function
>  which combines these variables and creates new ones into the same df
>  using "varX" as an identifier?
>
>  Many thanks,
>  Lauri
>
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-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O