Display percentage by column on a stacked bar graph

Question

I\'m trying to plot a stacked bar chart showing the relative percentages of each group within a column.

Here\'s an illustration of my problem, using the default mpg

Answer 1

If I compare your question to the link you gave than the difference is that the link "counted" them selves. That's what I did. I'am nor sure if this is than suitable for your real data.

library(ggplot2)
library(dplyr)

mpg %>%
  mutate(manufacturer = as.factor(manufacturer),
         class = as.factor(class)) %>%
  group_by(manufacturer, class) %>%
  summarise(count_class = n()) %>%
  group_by(manufacturer) %>%
  mutate(count_man = sum(count_class)) %>%
  mutate(percent = count_class / count_man * 100) %>%
  ggplot() +
  geom_bar(aes(x = manufacturer,
               y = count_man, 
               group = class,
               fill = class), 
           stat = "identity") +
  geom_text(aes(x = manufacturer,
                y = count_man,
                label = sprintf("%0.1f%%", percent)),
            position = position_stack(vjust = 0.5))

Edit, based on comment :

I made a mistake by selecting the wrong column for y

library(ggplot2)
library(dplyr)

mpg %>%
  mutate(manufacturer = as.factor(manufacturer),
         class = as.factor(class)) %>%
  group_by(manufacturer, class) %>%
  summarise(count_class = n()) %>%
  group_by(manufacturer) %>%
  mutate(count_man = sum(count_class)) %>%
  mutate(percent = count_class / count_man * 100) %>%
  ungroup() %>%
  ggplot(aes(x = manufacturer,
             y = count_class,
             group = class)) +
  geom_bar(aes(fill = class), 
           stat = "identity") +
  geom_text(aes(label = sprintf("%0.1f%%", percent)),
            position = position_stack(vjust = 0.5))