R stacked barplot with groups

Question

I'd like to create a stacked barchart with groups and am struggling with this:

data <- data.frame(timeslot=c("0-1", "1-2", "2-3", "3-4", "4-5", "5-6", "6-7", "7-8", "8-9", "9-10", "10-11", "11-12", "12-13", "13-14", "14-15", "15-16", "16-17", "17-18", "18-19", "19-20", "20-21", "21-22", "22-23", "23-0"),
Start1=c(3,0,1,0,0,1,2,22,58,41,30,41,52,52,38,35,20,18,14,19,12,2,9,0),
Start2=c(0,0,0,0,0,0,0,13,23,11,11,15,19,13,10,13,14,5,4,7,4,3,2,0),
Stop1=c(0,0,0,0,0,0,22,17,21,30,29,40,38,43,44,24,40,32,31,22,12,7,12,0),
Stop2=c(0,0,0,0,0,1,5,12,17,12,6,6,17,14,15,9,11,9,11,7,9,3,4,0))

Timeslots represents 1 hour intervals on a 24h day.
Now, I'd like to have two stacked bars for each interval, i.e. 0-1, 1-2, ..., 23-0.

The numbers in Start and Stop are counts for processes started and stoped during the given interval.

One bar should be Start1 and Start2 (stacked blue bar in image, darker blue for Start1, light blue Start2).
The other bar should be Stop1 and Stop2 (stacked brownish bar in image, lighter brown resembles Stop2).

Picture to show

This question is similar, but I couldn't get it to work with my data:

library(reshape2) # for melt
melted2 <- melt(data, "timeslot")
melted2$cat <- ''
melted2[melted$variable == 'value1',]$cat <- "Start1"
melted2[melted$variable == 'value2',]$cat <- "Start2"
melted2[melted$variable == 'value3',]$cat <- "Stop1"
melted2[melted$variable == 'value4',]$cat <- "Stop2"

ggplot(melted2, aes(x = cat, y = value, fill = variable)) + 
   geom_bar(stat = 'identity', position = 'stack') + facet_grid(~ timeslot)

Answer 1

I think this is what you wanted. As you can see I categorized the four variable types by the two categories "Start" and "Stop".

library(ggplot2)
data <- data.frame(timeslot=c("0-1", "1-2", "2-3", "3-4", "4-5", "5-6", "6-7", "7-8", "8-9", "9-10", "10-11", "11-12", "12-13", "13-14", "14-15", "15-16", "16-17", "17-18", "18-19", "19-20", "20-21", "21-22", "22-23", "23-0"),
                   Start1=c(3,0,1,0,0,1,2,22,58,41,30,41,52,52,38,35,20,18,14,19,12,2,9,0),
                   Start2=c(0,0,0,0,0,0,0,13,23,11,11,15,19,13,10,13,14,5,4,7,4,3,2,0),
                   Stop1=c(0,0,0,0,0,0,22,17,21,30,29,40,38,43,44,24,40,32,31,22,12,7,12,0),
                   Stop2=c(0,0,0,0,0,1,5,12,17,12,6,6,17,14,15,9,11,9,11,7,9,3,4,0))


library(reshape2) # for melt
melted <- melt(data, "timeslot")
melted$cat <- ''
melted[grep(melted$variable, pattern='Start'),]$cat <- "Start"
melted[grep(melted$variable, pattern='Stop'),]$cat <- "Stop"

melted$timeslot <- factor(melted$timeslot, levels=c("0-1", "1-2", "2-3", "3-4", "4-5", "5-6", "6-7", "7-8", "8-9", "9-10", "10-11", "11-12", "12-13", "13-14", "14-15", "15-16", "16-17", "17-18", "18-19", "19-20", "20-21", "21-22", "22-23", "23-0"))
ggplot(melted, aes(x = cat, y = value, fill = variable)) + 
  geom_bar(stat = 'identity', position = 'stack') + facet_grid(~ timeslot) +
  scale_fill_manual(values = c("royalblue3", "royalblue1", "#8B4513", "#B8860B")) +
  theme(legend.position = "bottom", axis.text.x = element_text(size=7))