Collapse rows with overlapping ranges

Question

I have a data.frame with start and end time:

ranges<- data.frame(start = c(65.72000,65.72187, 65.94312,73.75625,89.61625),stop = c(79.72187,79.72375,79.9         


        

Answer 1

Here is a data.table solution

library(data.table)
setDT(ranges)
ranges[, .(start=min(start), stop=max(stop)),
       by=.(group=cumsum(c(1, tail(start, -1) > head(stop, -1))))]
   group    start      stop
1:     1 65.72000  87.75625
2:     2 89.61625 104.94062

Here, groups are constructed by checking if the previous start is greater than stop and then using cumsum. within each group, minimum of start and maximum of stop are calculated.