There are many ways. You're making it overly complicated
Here, in an actual reproducible example (as you were requested to submit):
V <- data.frame(v1=c(1,0,0), v2=c("Shape", "Length", "Rate"),
stringsAsFactors=FALSE)
Finaldata <- data.frame(Shape = runif(5), Length = runif(5), Rate = runif(5))
# assuming names in V are not in the same order as columns in Finaldata
# also assuming there might accidentally be names not in Finaldata
Finaldata[, colnames(Finaldata) %in% V$v2[V$v1 == 0]]
# more elegant?
Finaldata[, colnames(Finaldata) %in% V$v2[!V$v1]]
# not robust to errors in V
Finaldata[, V$v2[!V$v1]]
# assumes order of column names matches order of V
Finaldata[, -V$v1]
Sarah
On Thu, Mar 27, 2014 at 11:09 AM, Sneha Bishnoi <sneha.bish...@gmail.com> wrote:
> Hi all!
>
> I am trying to drop columns from a data frame dynamically depending on user
> input. The dataframe whose columns need to be dropped is called "Finaldata"
> So here is what I do:
>
> V is a dataframe with columns v1 and v2 as follows
>
> v1 v2
> 1 1 Shape
> 2 0 Length
> 3 0 Rate
>
> v1 corresponds to user input, 1 if you want to drop the column, 0 otherwise
> v2 corresponds to column names of the all the columns in "Finaldata"
> I then use following code to drop columns
>
> for (i in 1:3)
> {
> if(V$v1[i]==1)
> {
> print(V$v2[i])
> Finaldata<-subset(Finaldata,select=-c(V$v2[i]))
> }
>
> }
>
> However v2 being type character is not accepted by subset.
> I read subset needs column names without quotes.
> I tried stripping off quotes through gsub and cat,however it din't help
> There are lot of columns and I cannot perform this individually on all
> columns.
> How do i go about it?
>
>
> Thanks!
> SB
>
--
Sarah Goslee
http://www.functionaldiversity.org
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