Collapse continuous integer runs to strings of ranges

Question

I have some data in a list that I need to look for continuous runs of integers (My brain thinkrle but don\'t know how to use it here).

It\'s easier to l

Answer 1

Another short solution with lapply and tapply:

lapply(z, function(x)
  unname(tapply(x, c(0, cumsum(diff(x) != 1)), FUN = function(y) 
    paste(unique(range(y)), collapse = ":")
  ))
)

The result:

$greg
[1] "7:11"  "20:24" "30:33" "49"   

$researcher
[1] "42:48"

$sally
[1] "25:29" "37:41"

$sam
[1] "1:6"   "16:19" "34:36"

$teacher
[1] "12:15"