[R] quote a column of a dataframe by its name

Rui Barradas ruipbarradas at sapo.pt
Fri Oct 4 18:14:02 CEST 2013


Hello,

I had no problems, and it shouldn't. What exactly do you mean by "not 
working"?

Hope this helps,

Rui Barradas

Em 04-10-2013 17:06, Jie escreveu:
> Dear All,
>
> I have a question, suppose X is a dataframe, with column names as
> "x1", "x2", "x3", ..... And I would like to use the i-th column by X[,'xi'].
> But it seems the single quote and double quote are different.
> So if I run X[, names(X)[i]], it has some error.
> Please use the below example code
>
> X = matrix(rnorm(50),ncol = 5)
> X = data.frame(X)
> names(X)=c("x1","x2","x3","x4","x5")
>
> #pick the 4-th column
> X[,'x4']  #working
> X[,names(X)[4]]  # not working , so how to modify this line?
>
> names(X)[4] #  returns "x4"
> sQuote(names(X)[4])  # returns "'x4'"
>
>
> Best,
>
> ______________________________________________
> R-help at r-project.org 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.
>



More information about the R-help mailing list