How to Circular Shift Vectors in R

We have provided a tip of how to circular shift lists in Python. Let’s see how we can do it in R by building our custom function.

custom_roll <- function( x , n ){
  if( n == 0 | n%%length(x)==0) {
    return(x)
    }
  
  else if (abs(n)>length(x)) {
  new_n<- (abs(n)%%length(x))*sign(n)
  return(c( tail(x,new_n) , head(x,-new_n) ))
  }
  else {
  return(c( tail(x,n) , head(x,-n) ))
  }
}

Let’s see what we get but taking into consideration the vector (1,2,3,4,5).

x<-c(1,2,3,4,5)
custom_roll(x,-11)

[1] 2 3 4 5 1

Or:

x<-c(1,2,3,4,5)
custom_roll(x,12)

[1] 4 5 1 2 3

Or a simpler example:

x<-c(1,2,3,4,5)
custom_roll(x,1)

[1] 5 1 2 3 4