[R] Dataframes and assign

[Göran Broström]

Douglas,

this was exactly what I needed! And new to me.

Thanks,

Göran

On 2 Oct 2002, Douglas Bates wrote:

> Göran Broström <gb at stat.umu.se> writes:
>
> > I have the following function:
> >
> > putsoc <- function(age, dat){
> >   ## age is an integer
> >   ## dat is a data.frame
> >
> >   new.name <- paste("soc", as.character(age), sep = ".")
> >   if (new.name %in% names(dat)) stop(paste(new.name, "already in place"))
> >
> >   dat$new.var <- rep(1, nrow(dat)) ## Just nonsense.
> >
> >   n.var <- ncol(dat)
> >   names(dat)[ncol(dat)] <- new.name
> >   return(dat)
> > }
>
> The $ operator is 'syntactic sugar' that allows you to write
> frm$colname instead of frm[['colname']].  In your case you are
> generating the name as a character string so you should use the second
> form.  That is, write your function as
>
> putsoc <- function(age, dat) {
>    new.name <- paste("soc", as.character(age), sep = ".")
>    if (new.name %in% names(dat)) stop(paste(new.name, "already in place"))
>
>    dat[[new.var]] <- rep(1, nrow(dat))
>    return(dat)
> }
>

---
 Göran Broström                    tel: +46 90 786 5223
 Department of Statistics          fax: +46 90 786 6614
 Umeå University                   http://www.stat.umu.se/egna/gb/
 SE-90187 Umeå, Sweden             e-mail: gb at stat.umu.se


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