[R] How to remove similar successive objects from a vector?

[Gavin Simpson]

On Wed, 2006-08-16 at 10:42 +0300, Atte Tenkanen wrote:
> Is there some (much) more efficient way to do this?
> 
> VECTOR=c(3,2,4,5,5,3,3,5,1,6,6);
> NEWVECTOR=VECTOR[1];
> 
> for(i in 1:(length(VECTOR)-1))
> {
> 	if((identical(VECTOR[i], VECTOR[i+1]))==FALSE){
> 		NEWVECTOR=c(NEWVECTOR,VECTOR[i+1])}
> }
> 
> > VECTOR
>  [1] 3 2 4 5 5 3 3 5 1 6 6
> > NEWVECTOR
> [1] 3 2 4 5 3 5 1 6
> 
> _______________________________
> Atte Tenkanen

Is this what you mean?

x <- c(3, 2, 4, 5, 5, 3, 3, 5, 1, 6, 6)
x.wanted <- c(3, 2, 4, 5, 3, 5, 1, 6)

X <- x[diff(x) != 0]

all.equal(x.wanted, X) # check it works

G
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Gavin Simpson                     [t] +44 (0)20 7679 0522
ECRC                              [f] +44 (0)20 7679 0565
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