Split a vector into chunks

Question

I have to split a vector into n chunks of equal size in R. I couldn\'t find any base function to do that. Also Google didn\'t get me anywhere. Here is what I came up with so

Answer 1

Here's another variant.

NOTE: with this sample you're specifying the CHUNK SIZE in the second parameter

1. all chunks are uniform, except for the last;
2. the last will at worst be smaller, never bigger than the chunk size.

chunk <- function(x,n)
{
    f <- sort(rep(1:(trunc(length(x)/n)+1),n))[1:length(x)]
    return(split(x,f))
}

#Test
n<-c(1,2,3,4,5,6,7,8,9,10,11)

c<-chunk(n,5)

q<-lapply(c, function(r) cat(r,sep=",",collapse="|") )
#output
1,2,3,4,5,|6,7,8,9,10,|11,|

Answer 2

I needed the same function and have read the previous solutions, however i also needed to have the unbalanced chunk to be at the end i.e if i have 10 elements to split them into vectors of 3 each, then my result should have vectors with 3,3,4 elements respectively. So i used the following (i left the code unoptimised for readability, otherwise no need to have many variables):

chunk <- function(x,n){
  numOfVectors <- floor(length(x)/n)
  elementsPerVector <- c(rep(n,numOfVectors-1),n+length(x) %% n)
  elemDistPerVector <- rep(1:numOfVectors,elementsPerVector)
  split(x,factor(elemDistPerVector))
}
set.seed(1)
x <- rnorm(10)
n <- 3
chunk(x,n)
$`1`
[1] -0.6264538  0.1836433 -0.8356286

$`2`
[1]  1.5952808  0.3295078 -0.8204684

$`3`
[1]  0.4874291  0.7383247  0.5757814 -0.3053884