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I have a bar chart in R using ggplot2 that shows different bars of different categories. Because some bar are = 0, I want to make a vertical line between the different categories so that they can be distinguished better visually.

I have already tried adding it through the panel.grid.major.x and panel.grid.minor.x arguments but that did not work. It would maybe also help if I can change the distance between the bars of the differnet categories instead of all of them when I do so with the width argument of geom_bar

Eg. in figure below: I want to add a vertical line and space between the purple bar of Cat 3 (Class 5) and the blue bar (Class 1) of Cat 4.

Example plot

Here is my code:

data <- categories.df
ggplot(data, aes(factor(Name, levels = c("Cat 1", "Cat 2", "Cat 3", "Cat 4", "Cat 5")), Count, fill = factor(SC_Class, levels = c("Class 1", "Class 2", "Class 3", "Class 4", "Class 5")))) +
    geom_bar(stat = "identity", position = position_dodge(width = 1), width = 0.8) +
    scale_fill_manual(values = c("#6C8EBF", "red", "#74767a", "orange","purple")) +
    labs(fill = "") +
    ylim(0,25) +
    xlab("Category") + ylab("Count") +
    theme(legend.position = c(1,1), legend.justification = c(1,1),
          axis.text.x = element_text(face = "bold", size=14),
          axis.text.y = element_text(face = "bold", size=14),
          axis.title.x = element_text(colour = "#6C8EBF", face = "bold", size =16),
          axis.title.y = element_text(colour = "#6C8EBF", face = "bold", size =16),
          panel.grid.major.y = element_line(size = 1, colour="#DAE8FC"),
          panel.grid.minor.y = element_line(colour="#DAE8FC"),
          panel.grid.major.x = element_blank(),
          panel.grid.minor.x = element_line(size = 1, colour="#DAE8FC"),
          plot.background = element_blank(),
          panel.background = element_blank(),
          panel.border = element_blank(),
          legend.text = element_text(size=12, face="bold"))

How can I add a vertical line and spaces between the different categories using ggplot2 in R?

Jelle
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  • Hi, your example is a little bit hard to read, because of many parameters that are not relevant to your question, like scales and theme options. Cleaning up your code before asking makes it easier to read and will probably get you more answers more quickly, this post on meta should help with that: https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example – snaut Feb 27 '19 at 11:55

1 Answers1

5

Use the position_dodge argument to your geom. I choose a more minimal example here, but you should be able to generalize it from there.

test <- data.frame(
  a=1:9,
  b=rep(letters[1:3], 3),
  c=rep(letters[1:3], each=3)
)

ggplot(test, aes(y=a, x=b, group=c, fill=c)) + 
  geom_col(position="dodge") +
  geom_vline(xintercept = 1.5)

(Based on this answer: ggplot side by side geom_bar())

snaut
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  • Great, thank you! I didn't realize a categorical x axis can also act as a continuous scale tpo create the vertical lines. – Jelle Feb 27 '19 at 12:20