[R] remove and put back elements in vector

[Uwe Ligges]

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);
> # 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"


In this case, you don't want to remove the elements, but calculate only 
on the others as in:

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

or

   b <- a
   b[b < 10] <- b[b < 10]^2

Uwe Ligges

> 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
> 
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