Hi Sarah,
Thanks! Do agree its over complicated.
However looking at the solutions I think I did not state my problem
completely.
V provides choices for only certain set of columns in Finaldata.
So v2 may not represent all columns of Finaldata.
I want to retain columns not provided as a choice for users plus the ones
user chooses to keep.
Thanks!
On Thu, Mar 27, 2014 at 11:30 AM, Sarah Goslee <sarah.gos...@gmail.com>wrote:
> 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
>
--
Sneha Bishnoi
+14047235469
H. Milton Stewart School of Industrial & Systems Engineering
Georgia Tech
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