[R] Translate the elements of a dataframe

[Gabor Grothendieck]

Try this:

2 * (DF == "+") - (DF != "-")


On Thu, Apr 16, 2009 at 2:58 PM, Juergen Rose <rose at rz.uni-potsdam.de> wrote:
> The second beginner question. I want to create a new dataframe, where
> each element of the original dataframe is translated to 1 if it was "+",
> to 0 if it was "-" to -1 otherwise. I could do with:
>
> Lines <- "a    b    c    d
>    +    -    +   +
>    +    +    +   -
>    +    1    -   '+ '
>    -    +    +   +
>    +    N    -   +"
>
>
> DF <- read.table(textConnection(Lines), header = TRUE)
> cnames <- colnames(DF)
> nrow <-length(rownames(DF))
>
> nc <- length(cnames)
> NDF <- data.frame(matrix(c(rep(0,nc*nrow)),ncol=nc))
>
> for (i in 1:length(cnames)) {
>  NDF[,i] <- sapply(DF[,i],function(x) if (x=="+") {1} else {if (x=="-")
> {0} else {-1}} )
> }
> colnames(NDF) <- cnames
>
> But this is shure one loop too much. Please give me the R way solution.
>
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