在饼图中添加值和百分比

Question

I'm trying to make a pie chart breaking down the split in values between 3 different categories (And yes I know a stacked bar chart would be better, but I don't really have a choice in the matter). I figured out how to make the pie using +coord_polar on a stacked bar plot, and hide the ticks/axis labels, but I need to include that actual values, as well as percentage of total, within each slice of the pie chart, and I'm not sure how to do that. Here's the code I'm using (the data I'm working with is confidential, so I've replaced it with some simulated data).

library(ggplot2)

simuldata <- data.frame(Category = LETTERS[1:3], 
                        value = c(196, 149,127))

piechart <- ggplot(simuldata, aes(x="", y=value, fill=Category)) +
  geom_bar(width=1, stat="identity") +
  coord_polar("y", start=0) +
  xlab("") +
  ylab("Value") +
  theme(axis.text.x=element_blank(),axis.ticks.x=element_blank())

piechart

How would I go about adding the values and percentages to each slice?

Answer 1

This is super-straightforward with the ggstatsplot package function ggpiestats ( https://cran.r-project.org/web/packages/ggstatsplot/vignettes/ggpiestats.html ):

# data
simuldata <- data.frame(Category = LETTERS[1:3],
                        value = c(196, 149, 127))

# plot
ggstatsplot::ggpiestats(data = simuldata,
                        main = Category,
                        counts = value)

^{Created on 2018-10-11 by the reprex package (v0.2.1)}

Answer 2

You can add a geom_text() layer, positioning each label to be stacked & vertically aligned in the middle:

piechart +
  geom_text(aes(label = paste0(value,
                               " (",
                               scales::percent(value / sum(value)),
                               ")")),
            position = position_stack(vjust = 0.5))