detect_continuous.R

detect_continuous <- function(src, gap = 1) {
  index.bool <- diff(src) == gap
  is.in_sequence <- FALSE
  start <- c()
  end <- c()
  for(i in 1:length(index.bool)) {
    if(!index.bool[i]) {
      is.in_sequence <- FALSE
    }
    if(index.bool[i] & !is.in_sequence) {
      start[length(start) + 1] <- i
      end[length(end) + 1] <- i+1
      is.in_sequence <- TRUE
      next
    }
    if(index.bool[i] & is.in_sequence) {
      end[length(end)] <- end[length(end)] + 1
      next
    }
  }  
  return(data.frame(start=start, end=end))
}

src <- c(2:6, 3:5, 1:10)
detect_continuous(src)
src[1:5]
src[6:8]
src[9:18]