[R] different behavior of $ with string literal vs string variable as argument
murdoch.duncan at gmail.com
Sun Feb 10 22:40:13 CET 2013
On 13-02-10 4:06 PM, David Romano wrote:
> Hi everyone,
> I ran into the issue below while trying to execute a command of the form
> apply(list.names,1, function(x) F(favorite.list$x) )
> where list.names is a character vector containing the names of the elements
> of favorite.list and F is some function defined on a list element.
> Namely, the $ operator doesn't treat the string variable 'x' as the string
> it represents, so that, e.g.
>> ll <- list(ss="abc")
>  "abc"
>  "abc"
>> name <- "ss"
> I can get around this by using integers and the [[ and [ operators, but I'd
> like to be able to use names directly, too -- how would I go about doing
> Thanks for your help in clarifying what might be going on here.
You can use names with [[, e.g.
will work in your example. You can see more details in the help topic
help("$"), in the section "Recursive (list-like) objects".
More information about the R-help