Question

I’m beginning to analyse datas for my thesis. I first need to count consecutive occurences of strings as one. Here’s a sample vector :

test <- c("vv","vv","vv","bb","bb","bb","","cc","cc","vv","vv")

I would like to simply extract unique values, as in the unix command uniq. So expected output would be a vector as :

“vv”,”bb”,”cc”,”vv”

I looked at rle function, wich seems to be fine, but how would I get the output of rle as a vector ? I don’t seem to understand the rle class…

> rle(test)
Run Length Encoding
  lengths: int [1:5] 3 3 1 2 2
  values : chr [1:5] "vv" "bb" "" "cc" "vv"

How to get one vector of the values output by rle and another one for the lengths ? Hope I’m making myself clear…

Thanks again for any help !

Answer 1

rle() returns a two-element list of class "rle"; as @gsk points out, you can use ordinary list-indexing constructs to access the component vectors.

Also, try this, to put the results of rle into a more familiar format:

as.data.frame(rev(unclass(rle(test))))
#   values lengths
# 1     vv       3
# 2     bb       3
# 3              1
# 4     cc       2
# 5     vv       2