[R] Remove non-numerical columns from data frame

[Henrique Dallazuanna]

Try this:

x <- data.frame(A=c(10,20), B = c("a", "b"), C = c(20,30))
x[sapply(x, is.numeric)]

On Sat, Jul 26, 2008 at 11:19 AM, Markus Mühlbacher <muehliman at yahoo.com> wrote:
> Hello,
>
> My question sounds simple, but as I am desperatly searchin for a solution I am
> asking you all. :)
>
> I try to filter out all non-numeric columns of a data frame using a for loop
> to go through all columns. My if clause looks like this:
>
>         for(j in 1:length(data)) {
>
>                 ...
>                 if(!is.numeric(data[j])) skip <- "not numeric")
>                 ...
>         }
>
> When I do: is.numeric(data$vol) i get TRUE as result:
> unfortunately this is not applicable in a for loop, because i need to go
> through all of the columns using j.
> I also tried to paste data$ and the name of the column , but this is always a
> character.
>
> When I do: is.numeric(data[257]) i get FALSE as result
> (257 is the corresponding column index to "vol")
>
> Help needed! Thanks!
> Markus
>
>
>
>
>
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>
>
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>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O