Generate a repeating sequence

Question

I need to generate a vector of the following format using R:

1:10, 1:10, 11:20, 11:20, ... 121:130, 121:130

Is there an easier way than creating 12 vectors and then repeating each one twice?

Answer 1

Is this what you want?

unlist(lapply(rep(seq(1, 121, by=10), each=2), function(x) seq(x, x+9)))

Answer 2

Also you could do:

rep(1:10, 26) + rep(seq(0,120,10), each=20)

Answer 3

Another way:

x <- matrix(1:130, 10, 13)
c(rbind(x, x))

---

Possible more efficient version:

x <- 1:130
dim(x) <- c(10,13)
c(rbind(x, x))

Answer 4

Alternatively, you could use a combination of rep and outer, such as:

c(outer(1:10,rep(0:12,each=2),function(x,y)10*y+x))

Answer 5

I think this will do you.

x <- ((0:12)*10)+1
y <- x + 9

repeatVectors <- function(x,y){
    rep(seq(x,y),2)
}

z <- mapply(repeatVectors, x,y)
z <- as.vector(z)

Answer 6

A method using split is

unlist(rep(split(seq_len(130), rep(1:13, each=10)), each=2), use.names=FALSE)