On 27/08/2013 4:38 PM, Rolf Turner wrote:
Actually what's needed is "deparse(substitute(...))":
file = paste(deparse(substitute(x)),"csv",sep="."))
I have no idea what "deparse" and "substitute" really mean; I just treat
the forgoing as a black box/magic incantation. It works.
In case anyone is interested:
Until you change them, arguments to functions are stored as "promises".
Those start out as an expression to evaluate, and a flag saying it
hasn't been evaluated yet. In most code, the first time you use the
argument, it gets evaluated, the flag gets flipped, and the value gets
saved. After that you just see the value.
Using substitute(x) when x is a promise will return the expression,
whether it has been evaluated or not.
But that expression is a bit of R language, it's not a character string.
Calling deparse() on it converts it to a character string
representation of it.
So now you know.
Duncan Murdoch
cheers,
Rolf Turner
On 28/08/13 09:19, Hadley Wickham wrote:
It's not really the inverse of assign (that's get), but I think you
want substitute.
See http://adv-r.had.co.nz/Computing-on-the-language.html for more details.
Hadley
On Tue, Aug 27, 2013 at 4:13 PM, Robert Lynch<robert.b.ly...@gmail.com> wrote:
I am looking for a way to extract the name of a variable that has been
passed into a function
for example
foo<-function(x){
write.csv(x, file = paste(NAME(x), "csv", sep ="."))
}
is there a function "NAME" that would let the calls
foo(bar)
write the file bar.csv
and foo(stuff)
write the file stuff.csv
Robert
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