I did not realize that ++ was available. Is there a comprehensive list
somewhere of which operators are available for definition? I searched
the R Language manual for ++ but that only came up with a reference to C++ .
On 17 Nov 2006 11:38:43 +0100, Peter Dalgaard <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] writes:
>
> > Hi,
> >
> > You could stack your list in an array and then use apply :
> >
> > myArray <- array( unlist(lapply(1:3, f) ) , dim =c(2, 3, 3))
> > apply(myArray, c(1,2), sum)
>
> Or fixup "+" to take more than two arguments, e.g.
>
> "++" <- function(x, ...) if (nargs() == 1) x else x + Recall(...)
>
> f <- function(i){matrix((1:6)^i, 2, 3)}
> do.call("++", sapply(1:4, f, simplify=FALSE))
>
> ##
>
> > "++" <- function(x, ...) if (nargs() == 1) x else x + Recall(...)
> > f <- function(i){matrix((1:6)^i, 2, 3)}
> > do.call("++", sapply(1:4, f, simplify=FALSE))
> [,1] [,2] [,3]
> [1,] 4 120 780
> [2,] 30 340 1554
>
>
>
>
> > Cheers,
> >
> > Romain
> >
> > Quoting Robin Hankin <[EMAIL PROTECTED]>:
> >
> > > Hi
> > >
> > > How do I make do.call() take "+" as a function for a list of more
> > > than two elements?
> > >
> > > Toy problem follows:
> > >
> > >
> > > f <- function(i){matrix((1:6)^i,2,3)}
> > >
> > > # Thus f() returns a matrix of size 2x3; I want to add a whole bunch
> > > of such matrices,
> > > # as in f(1) + f(2) + f(3) + f(4)
> > >
> > > # But:
> > >
> > >
> > >
> > > > do.call("+",sapply(1:4,f,simplify=FALSE))
> > > Error in do.call("+", sapply(1:4, f, simplify = FALSE)) :
> > > operator needs one or two arguments
> > >
> > >
> > >
> > >
> > > Also,
> > >
> > >
> > > > do.call(sum,sapply(1:4,f,simplify=FALSE))
> > > [1] 2828
> > >
> > >
> > > doesn't do what I want (I would like a 2x3 matrix whose elements are the
> > > sum of corresponding elements in my list)
> > >
> > > How to do this nicely?
> > >
> > >
> > >
> > >
> > >
> > > --
> > > Robin Hankin
> > > Uncertainty Analyst
> > > National Oceanography Centre, Southampton
> > > European Way, Southampton SO14 3ZH, UK
> > > tel 023-8059-7743
> > >
> > > ______________________________________________
> > > R-help@stat.math.ethz.ch mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > PLEASE do read the posting guide
> > > http://www.R-project.org/posting-guide.html
> > > and provide commented, minimal, self-contained, reproducible code.
> > >
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
> --
> O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
> c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
> (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
> ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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