> > This is driving me nuts. I have a 3-D array that holds x,y,z
> > coordinates from multiple experiments. I need to clean the
> data before
> > making it sp objects. I want to set all z-values < 0 to 0. In a 2-D
> > matrix this is trivial e.g., x[,x[1,]<0] <- 0. But I'm
> stumped on how
> > to do this on a 3-D array without a loop. Given an array:
> >
> > foo <- array(rnorm(24), dim=c(4,3,2))
> > dimnames(foo) <-
> list(NULL,c('x','y','z'),c('Experiment1','Experiment2'))
> > foo[,'z',]
> >
> > How can I set foo[,'z',]<0 to 0?
>
> a <- array(rnorm(64), c(4,4,4))
> inds <- which(a < 0, arr.ind=TRUE)
> a[inds] <- 0
>
Thanks, but I'm looking to set only the values from one dimension to zero.
As above, I just want to set the 'z' values to 0 if they are less than one.
This works:
foo <- array(rnorm(24), dim=c(4,3,2))
dimnames(foo) <-list(NULL,c('x','y','z'),c('Experiment1','Experiment2'))
foo[,'z',]
#How can I set foo[,'z',]<0 to 0
for(i in 1:2){
foo[foo[,'z',i]<0,'z',i] = 0
}
foo
But it seems like one should be able to do this with apply or just '['. I'm
at a loss.
-A
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