[R] Variable names conflict

[Adams, Jean]

Axel,

The solution you propose looks fine to me, if an error is the outcome that
you want in such a situation.  Were you hoping for a different outcome?
Would you, for example, prefer that the "x" in the data frame be given a
different name, rather than the "x" in the function?

Jean

On Thu, Oct 15, 2015 at 11:42 AM, Axel Urbiz <axel.urbiz at gmail.com> wrote:

> Hello,
>
> I have a variable named 'x' defined inside a function, which   may conflict
> with a variable name supplied in the argument to the function. What is the
> best practice to avoid this conflict?
>
> foo <- function(df) {
>   x <- df[, 1, drop = FALSE]
>   dfOut <- data.frame(df, x)
>   dfOut
>
> }
> Data <- data.frame(x = c(1, 2), y = c(3, 4))
> foo(Data)
>
>   x y x.1
> 1 1 3   1
> 2 2 4   2
>
> The following solution doesn't look nice to me…
>
> foo <- function(df) {
>   if (any(names(df) == 'x'))
>     stop("x cannot be a variable name in the data frame")
>   x <- df[, 1, drop = FALSE]
>   dfOut <- data.frame(df, x)
>   dfOut
>
> }
>
> Thanks!
> Axel.
>
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>
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