That worked, and helped my understanding.? Thank you. ---------------------------------------- Hello, You have to load the packages involved: library(dplyr) library(tidyr) library(ggplot2) then run the full sequence. Though this is not important, if you are pivotting columnns named y1 and y2, why not name the result just y? pivot_longer(-time, names_to = "y") And here is complete code, runs in a fresh R session. tst? <- read.table(text = " time y1 y2 1? 18:55 30 19 2? 18:56 30 19 3? 18:57 29 19 4? 18:58 31 19 5? 18:59 28 19 6? 19:00 28 19 7? 19:01 28 19 8? 19:02 28 19 9? 19:03 28 19 10 19:04 28 19 11 19:05 29 19 ", header = TRUE) library(dplyr) library(tidyr) library(ggplot2) tst %>% ?? mutate(time = paste(Sys.Date(), time), ????????? time = as.POSIXct(time)) %>% ?? select(time, y1, y2) %>% ?? # reshape to long format ?? pivot_longer(-time, names_to = "y") %>% ?? # now plot ?? ggplot(aes(time, value, color = y)) + ?? geom_line() + ?? geom_point() + ?? scale_color_manual(values = c("orange", "skyblue")) + ?? # make datetime labels ?? scale_x_datetime(date_breaks = "1 mins", date_labels = "%H:%M") + ?? theme_bw() Hope this helps, Rui Barradas [[alternative HTML version deleted]]