r - How to plot a Stacked and grouped bar chart in ggplot?

Question

I have a data frame like below:

id    month     type    count
___  _______   ______   ______
1      1          1       10
1      1          2       09
1      1          3       26
1      2          1       60
1      2          2       90
2      2          3       80
2      1          1       10
2      1          2       09
2      1          3       26
2      2          1       60
2      2          2       90
2      2          3       80
3      1          1       10
3      1          2       09
3      1          3       26
3      2          1       60
3      2          2       90
3      2          3       80

I thought the best way to visualize is a stacked group bar something like the below:

So I tried with

ggplot(df,aes(x=id,y=count,fill=month))+geom_bar(stat="identity",position=position_dodge())+geom_text(aes(label=count),size=3)

Which gave a plot which was a bit different than my expectation.Any help is appreciated.

Answer 1

Suppose you want to plot id as x-axis, side by side for the month, and stack different types, you can split data frame by month, and add a bar layer for each month, shift the x by an amount for the second month bars so they can be separated:

barwidth = 0.35

month_one <- filter(df, month == 1) %>% 
    group_by(id) %>% arrange(-type) %>% 
    mutate(pos = cumsum(count) - count / 2)   # calculate the position of the label

month_two <- filter(df, month == 2) %>% 
    group_by(id) %>% arrange(-type) %>% 
    mutate(pos = cumsum(count) - count / 2)

ggplot() + 
    geom_bar(data = month_one, 
             mapping = aes(x = id, y = count, fill = as.factor(type)), 
             stat="identity", 
             position='stack', 
             width = barwidth) + 
    geom_text(data = month_one, 
              aes(x = id, y = pos, label = count )) + 
    geom_bar(data = filter(df, month==2), 
             mapping = aes(x = id + barwidth + 0.01, y = count, fill = as.factor(type)), 
             stat="identity", 
             position='stack' , 
             width = barwidth) + 
    geom_text(data = month_two, 
              aes(x = id + barwidth + 0.01, y = pos, label = count )) + 
    labs(fill  = "type")

gives:

---

dput(df)
structure(list(id = c(1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 
2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L), month = c(1L, 1L, 1L, 2L, 2L, 
2L, 1L, 1L, 1L, 2L, 2L, 2L, 1L, 1L, 1L, 2L, 2L, 2L), type = c(1L, 
2L, 3L, 1L, 2L, 3L, 1L, 2L, 3L, 1L, 2L, 3L, 1L, 2L, 3L, 1L, 2L, 
3L), count = c(10L, 9L, 26L, 60L, 90L, 80L, 10L, 9L, 26L, 60L, 
90L, 80L, 10L, 9L, 26L, 60L, 90L, 80L)), .Names = c("id", "month", 
"type", "count"), class = "data.frame", row.names = c(NA, -18L
))