Plot axis of different lengths and then lines

Question

Ok, I'm really struggling with this. I've tried to read various answers on StackOverflow but didn't find te solution. So here it is:

I have clients ids, and have time of operations. I also have time intervals associated with clients waiting in the queue. I want to plot lines representing the clients waiting time onto the plot where xlab: hours of operations, ylab: client.

Data:

 [1] "2011-05-12 08:00:00 " "2011-05-12 09:00:00 "
 [3] "2011-05-12 10:00:00 " "2011-05-12 11:00:00 "
 [5] "2011-05-12 12:00:00 " "2011-05-12 13:00:00 "
 [7] "2011-05-12 14:00:00 " "2011-05-12 15:00:00 "
 [9] "2011-05-12 16:00:00 " "2011-05-12 17:00:00 "
[11] "2011-05-12 18:00:00 " "2011-05-12 19:00:00 "
[13] "2011-05-12 20:00:00 "

by the way, have two questions here: 1. is there any convinient way to store time without date? Like "19:00:00" 2. How can I create seq of time with min

clients[1:10]
 [1] G155 H54  G157 G158 J52  A51  C52  D52  G151 Y51 

Then I have time for every client:

xcl[1:3,]
             StartTime            NextTime             EndTime TrackNo
33 2011-04-29 19:15:57 2011-04-29 19:20:04 2011-04-29 19:23:13    G155
34 2011-04-29 19:16:06 2011-04-29 19:25:41 2011-04-29 19:26:13     H54
36 2011-04-29 19:45:56 2011-04-29 19:47:58 2011-04-29 19:48:42    G157

So I can calc the waiting time and time of operation. I want to draw horizontal lines to represent that. How am I to do it?

Answer 1

DF <- read.table(text="StartTime,NextTime,EndTime,TrackNo
33,2011-04-29 19:15:57,2011-04-29 19:20:04,2011-04-29 19:23:13,G155
34,2011-04-29 19:16:06,2011-04-29 19:25:41,2011-04-29 19:26:13,H54
36,2011-04-29 19:45:56,2011-04-29 19:47:58,2011-04-29 19:48:42,G157", header=TRUE, sep=",", stringsAsFactors=FALSE)

#make datetimes POSXct objects
DF[,1:3] <- do.call(cbind.data.frame,lapply(DF[,1:3], as.POSIXct, format="%Y-%m-%d %H:%M:%S", tz="GMT"))

#discard date information
DF <- cbind(DF, do.call(cbind.data.frame,lapply(DF[,1:3], function(x) as.POSIXct(format(x, "%H:%M:%S"), format="%H:%M:%S", tz="GMT"))))
names(DF)[5:7] <- paste0(names(DF)[5:7],1)

library(ggplot2)

p <- ggplot(DF, aes(y=TrackNo, yend=TrackNo)) +
  geom_segment(aes(x=StartTime1, xend=NextTime1), colour="red", size=2) +
  geom_segment(aes(x=NextTime1, xend=EndTime1), colour="green", size=2) +
  theme_classic(base_size=23) +
  xlab("Time") +
  ylab("")

print(p)