[R] applying a function over an array

Gabor Grothendieck ggrothendieck at gmail.com
Wed May 18 16:26:18 CEST 2005

On 5/18/05, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> On 5/18/05, BJ <erithid at bellsouth.net> wrote:
> > Is there a way to apply a function with several arguements over an
> > array? For instance if you had a function d<-function(a,b,c) {a+b+c} and
> > a 4,3 array, could you apply the function over each line of the array?
> > tapply seems to only allow one argument, and I just can't think of a way
> > to explicitly tell R that I am passing it 3 distinct objects instead of
> > 1 complex one.  Thank you as always for your help. ~Erithid
> If x is the 4x3 array:
> mapply(d, x[,1], x[,2], x[,3])

Also you might check if your d is vectorized already (it is in your 
example) in which case you can just do:

   d(x[,1], x[,2], x[,3])

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