Thanks Bill, That is what I was looking for. Gerrit On 12/29/2014 05:53 PM, William Dunlap wrote:
as.vector(x) will return x without any attributes and structure(x, attrA=NULL, attrB=NULL) will return x without the named attributes. > z <- f(1:3, 4) > z [1] 14 attr(,"gradient") [1] -6 -4 -2 > as.vector(z) [1] 14 > structure(z, gradient=NULL) [1] 14as.vector is a generic function, so for certain classes (e.g., factor) it may do more than just strip attributes. Matrix dimensions are attributes and will be removed by as.vector. Bill Dunlap TIBCO Software wdunlap tibco.com <http://tibco.com> On Mon, Dec 29, 2014 at 8:17 AM, Gerrit Draisma <gdrai...@xs4all.nl <mailto:gdrai...@xs4all.nl>> wrote: Thanks Duncan. But my question was how to extract simply the function value from value, without the gradient attribute? I see that things like value<2 give the right answer. I was curiosity. I found now that value[1] gives strips the attributes from value: ------ > value [1] 1 attr(,"gradient") [1] 2 > value[1] [1] 1 ------ Is that the way? Gerrit On 12/29/2014 05:05 PM, Duncan Murdoch wrote: On 29/12/2014 10:32 AM, Gerrit Draisma wrote: Just a curiosity question: In the documentation for the nlm procedure a find this example of defining a function with a gradient attribute: ----------- f <- function(x, a) { res <- sum((x-a)^2) attr(res, "gradient") <- 2*(x-a) res } ----------- I get the gradient with attr(f(3,2),"gradient") but how do I get the function value it self? value <- f(3,2) gradient <- attr(value, "gradient") Duncan Murdoch ________________________________________________ R-help@r-project.org <mailto:R-help@r-project.org> mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/__listinfo/r-help <https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide http://www.R-project.org/__posting-guide.html <http://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code.
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