R - create a sequence of odd numbers followed by the sequence of even numbers on the same interval-CodePudding

So I am basically looking for a more efficient way to do this:

c(seq(1, 5, 2), seq(2, 6, 2))

Is there a simpler function built in R or some of the packages that would allow me to specify just one interval (from 1 to 6; instead of having to specify from 1 to 5 and from 2 to 6), but to sort the numbers so that all the odd numbers appear before the even ones?

CodePudding user response：

Just concatenate the sub-data that contains only odd numbers of the original data and the other sub-data that contains the remaining even numbers.

In the following, you can have the original data x1, which consists of 10 integers from a poisson distribution of mean 8 (rpois(n = 10, lambda = 8)), and merge the sub-data of odd numbers (x1[x1 %% 2 == 1]) and that of even numbers (x1[x1 %% 2 == 0]).

## To prepare data
x1 <- rpois(n = 10, lambda = 8)
x1

## To sort the data so that odd numbers come earlier
c(x1[x1 %% 2 == 1], x1[x1 %% 2 == 0])

CodePudding user response：

You can use sequence. The first argument of the function is the length of each sequence, from is the starting point, and by is the interval.

sequence(c(3, 3), from = c(1, 2), by = 2)
#[1] 1 3 5 2 4 6

Or, as a function that fits your request:

seqOrdered <- function(from = 1, to){
  n = ceiling((to - from) / 2)
  sequence(c(n, n), from = c(from, from   1), by = 2)
}

seqOrdered(1, 6)
#[1] 1 3 5 2 4 6