On 04/08/2010 7:47 AM, Liviu Andronic wrote:
Dear all
Is there an easier way to retrieve the name of an object? For example,
> tmp <- 1:10
> as.character(quote(tmp))
[1] "tmp"
> as.character(quote(mtcars$cyl))
[1] "$" "mtcars" "cyl"
> as.character(quote(mtcars$cyl))[3]
[1] "cyl"
The last call more than anything seems a hack. Is there a better way?
I don't understand what you want. "cyl" is not the name of an object;
it's the name of a component of the mtcars object. If you know that,
you can simply use names(mtcars) to get all the names, and
names(mtcars)[2] to get "cyl".
Perhaps you thought the result of the expression mtcars$cyl was an
object whose name was "cyl"? It's not. Unless you assign it to
something, it's an anonymous object.
As other have pointed out, in a function you can use substitute(arg) to
retrieve the expression passed as arg, and deparse(substitute(arg)) to
turn it into a string that's suitable for using as a label. But that's
not the name of the object. The name of the object in that case is "arg".
Duncan Murdoch
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