Force bars/rows in stacked bar chart (ggplot showing percent, zero decimal places) to be of same lenght?

Question

I am new to R and I need to create a stacked bar chart which shows percent within bars (stacks) and goes from 0 to 100 percent. I have over 7000 rows and 12 vectors that range from value 1 trough 5 (the value 9999 is to be excluded from the chart). For each vector I have calculated a percentage over the 5 values, so that each bar in the chart should sum to 100 %.

The problem I encounter is this: Two of the vectors sum to 99 % and one vector sums to 101 %, while the rest sum to 100 as expected. The chart therefore has two bars/rows that are a bit shorter and one bar/row that is a bit longer than the rest of the bars. This problem disappears if I round to 1 or 2 decimal places, rather than asking for 0 decimal places (which, sadly, is what I have to do).

Is there any way to force ggplot to show bars/rows of identical length (100 %) ?

Any help is greatly appreciated!

EDIT!

I removed the two images of my data and the ggplot. I have produced a working example which simulates my data and shows how bars/rows differ in lenght when I ask for 0 decimal places.

I am well aware that this issue could be solved by asking for 1 decimal place. My employer wants 0, which is why I hope to find a solution for this.

library(reprex)
library(ggplot2)
library(tidyverse)


# Creating some data

item1 <- floor(runif(7200, min=1, max=6))
item2 <- floor(runif(7200, min=1, max=6))
item3 <- floor(runif(7200, min=1, max=6))
item4 <- floor(runif(7200, min=1, max=6))
item5 <- floor(runif(7200, min=1, max=6))
item6 <- floor(runif(7200, min=1, max=6))
item7 <- floor(runif(7200, min=1, max=6))
item8 <- floor(runif(7200, min=1, max=6))
item9 <- floor(runif(7200, min=1, max=6))
item10 <- floor(runif(7200, min=1, max=6))
item11 <- floor(runif(7200, min=1, max=6))
item12 <- floor(runif(7200, min=1, max=6))


df <- data.frame(item1, item2, item3, item4, item5, item6, item7, item8, item9, item10, item11, item12)


# Drawing the ggplot with 0 (zero) decimal places

df %>%
    gather %>% 
    group_by(key, value) %>%
    tally %>%
    mutate(n = round(n/sum(n)*100,0)) %>%
    ggplot(aes(x=key, y=n, fill=as.factor(value))) + 
    geom_col(position = position_stack(reverse = T)) +
    labs(title = "Some title", x = " ", y = "%", fill = " ") +
    geom_text(aes(label=n), position=position_stack(reverse = TRUE, vjust = 0.5), size = 3, colour = "white") +
    theme(legend.position="top") +
    coord_flip() +
    theme_minimal()

^{Created on 2022-04-06 by the reprex package (v2.0.1)}

I think you're just looking for `geom_col(position = position_fill(reverse = T))` — Dan Adams, Apr 05 '22 at 22:36
Why do you have to limit the precision of your rounding? Is it just for display? You can do that just in the displayed value so that your bars come out the correct length. — Dan Adams, Apr 05 '22 at 22:45

Dan Adams · Accepted Answer · 2022-04-06T20:29:07.450

0

A very simple solution to your problem is to change from position = position_stack() to position = position_fill().

library(tidyverse)
library(scales)

# Creating some data
df <- data.frame(matrix(floor(runif(12*7200, 1, 6)), ncol = 12, dimnames = list(NULL, paste0("item", 1:12))))

# Drawing the ggplot with 0 (zero) decimal places
df %>%
  gather %>% 
  group_by(key, value) %>%
  tally %>%
  mutate(n = round(n/sum(n) * 100, 0)) %>%
  ggplot(aes(x = key, y = n, fill = as.factor(value))) + 
  geom_col(position = position_fill(reverse = T)) +
  labs(title = "Some title", x = " ", fill = " ") +
  scale_y_continuous(name = "%", labels = percent) +
  geom_text(aes(label = n), position = position_fill(reverse = TRUE, vjust = 0.5), size = 3, colour = "white") +
  theme(legend.position = "top") +
  coord_flip() +
  theme_minimal()

^{Created on 2022-04-06 by the reprex package (v2.0.1)}

edited Apr 06 '22 at 20:29

answered Apr 05 '22 at 22:51

Dan Adams

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Thank you for the example, @DanAdams. I tried to implement it in my code, but it did not work on my data. I have now provided a working example which better illustrates the nature of my data. If you have any other suggestions I would really apprieciate it. – Thalelia Apr 06 '22 at 15:23
Wow! Thank you so much, this is exacly what I needed! I also got to learn a better way of creating the vectors and data. :-) Thank you for taking the time to help me with this @DanAdams, I am truly grateful. – Thalelia Apr 07 '22 at 22:20

Force bars/rows in stacked bar chart (ggplot showing percent, zero decimal places) to be of same lenght?

EDIT!

1 Answers1