Additional clarification: the problem only comes when you have one column
selected from the original dataframe. You need to make the following
modification to the original example:
data.df <- data.frame(aa=c(1,1,0), cc=c(1,0,0), aab=c(0,1,0), aac=c(0,0,1),
bb=c(1,0,1))
And, the following seems to work:
data.frame(sapply(col2.uniq, function(col) {
wcol <- which(col==col2)
as.numeric(rowSums(data.frame(data.df[,wcol]))>0)
}))
I had to wrap data.df[,wcol] in another data.frame to handle situations where
wcol had one element. Is there a better approach?
---- Chuck White <[email protected]> wrote:
> Hello -- I am trying to merge columns in a dataframe based on substring
> matches in colnames. I would appreciate if somebody can suggest a
> faster/cleaner approach (eg. I would have really liked to avoid the if-else
> piece but rowSums does not like that). Thanks.
>
> data.df <- data.frame(aa=c(1,1,0), bbcc=c(1,0,0), aab=c(0,1,0), aac=c(0,0,1),
> bbk=c(1,0,1))
> col2 <- substr(colnames(data.df),1,2)
>
> col2.uniq <- unique(col2)
> names(col2.uniq) <- col2.uniq
>
> data.frame(sapply(col2.uniq, function(col) {
> wcol <- which(col==col2)
> if(length(wcol)>1) {
> tmp <- rowSums(data.df[,wcol])
> } else {
> tmp <- data.df[,wcol]
> }
> as.numeric(tmp>0)
> }))
______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
