# [R] remove and put back elements in vector

Thu Jul 17 13:28:29 CEST 2003

```Would a simple ifelse() do ?

a <- ifelse( a < 10, a^2, a )

On Thu, 17 Jul 2003, Torsten Hothorn wrote:

>
>
> On Thu, 17 Jul 2003, Angel wrote:
>
> >
> > Hi,
> > How can I remove elements from a vector and them put them back in place??
> > An example (very simple, my vector/operations are much larger/complicated):
> > Got a vector, lets say:
> >  a<-c(1,2,40,10,3,20,6);
>
>
> you need to save the index of the elements of interest:
>
> R> a<-c(1,2,40,10,3,20,6)
> R> indx <- which(a < 10)
> R> b <- a[indx]
> R> b <- b^2
> R> a[indx] <- b
> R> a
> [1]  1  4 40 10  9 20 36
>
> and similar with b
>
> Torsten
>
> > # I remove values larger than 10
> > a<-a[a<10]
> > # Do some operations on the new a "1 2 3 6"
> > b<-a^2
> > # Now b is "[1]  1  4  9 36"
> > # Now I want to insert the elements I removed in a back into a and b
> > # so I get:
> > # a       "1 2 40 10 3 20 6"
> > #and b "1 4 40 10 9 20 36"
> >
> > The only thing I've found on the archives is explanations on how to insert:
> > http://maths.newcastle.edu.au/~rking/R/help/03a/1794.html
> > Thanks,
> > Angel
> >
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> >
> >
>
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>

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