Split a vector into unequal chunks in R

Question

I have the same question as here, except I want to specify the variable split lengths with another vector. So, something like this:

example.data<-paste("ex",1:10,sep="")
example.data
 [1] "ex1"  "ex2"  "ex3"  "ex4"  "ex5"  "ex6"  "ex7"  "ex8"  "ex9"  "ex10"
split.lens <- c(4,2,1,3)

should give me the following list:

result.list
[[1]]
[1] "ex1" "ex2" "ex3" "ex4"

[[2]]
[1] "ex5" "ex6"

[[3]]
[1] "ex7"

[[4]]
[1] "ex8"  "ex9"  "ex10"

I can't figure out the best way to do this with split. Any ideas?

Thanks!

score 13 · Accepted Answer · answered Dec 09 '14 at 21:05

13

split(example.data, rep(1:4, c(4,2,1,3)))

answered Dec 09 '14 at 21:05

DatamineR

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Thank you. So simple...and yet: R. I appreciate the help. – Plastic Soul Dec 09 '14 at 21:10
You are welcome! It would be nice if you accepted the answer if it was useful for you... – DatamineR Dec 09 '14 at 21:13
had to wait for the 6 minute time limit :) – Plastic Soul Dec 09 '14 at 21:19
2

Less hard coded (more programmatic) would be `rep(seq_along(split.lens), split.lens)` if we assume they had already created the `split.lens` object. (+1) – A5C1D2H2I1M1N2O1R2T1 Dec 10 '14 at 02:08

score 4 · Answer 2 · answered Dec 09 '14 at 22:26

I have added a more general method to the dev version of qdapTools to split various data types at specific locations. Here is that approach:

## install qdapTools
devtools::install_github("trinker/qdapTools")

library(qdapTools)
loc_split(example.data, head(cumsum(split.lens) + 1, -1))

## [[1]]
## [1] "ex1" "ex2" "ex3" "ex4"
## 
## [[2]]
## [1] "ex5" "ex6"
## 
## [[3]]
## [1] "ex7"
## 
## [[4]]
## [1] "ex8"  "ex9"  "ex10"

The function essentially wraps code similar to @RStudent's answer when applied to vectors.

More to check in qdap and qdapTools. So many functions to learn. This is a nice function. :) — jazzurro, Dec 10 '14 at 00:31

Split a vector into unequal chunks in R

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