How can I use geom_text
to add percentage labels on top of each bar in ggplot2
? I know there are several similar questions which are already answered. But they either use only 1 categorical variable or compute the percentages before plotting.
I have following plot:
ggplot(data = mtcars)+
geom_bar(aes(x = factor(cyl),
y = (..count..)/sum(..count..)*100,
fill = factor(gear)),
position = "dodge")
Now I want to add the percentage labels on the top. If I use y = (..count..)/sum(..count..)*100
in geom_text
, it says Error in eval(expr, envir, enclos) : object 'count' not found
.
We can improve the barplot further by labeling the percentage values directly on the bars with percent symbols. To do that, we will use label argument with scales' percent function. And use geom_text() function to add the labels with percentage symbol on bars.
To add labels on top of each bar in Barplot in R we use the geom_text() function of the ggplot2 package. Parameters: value: value field of which labels have to display.
Since we need to add percentages in the labels of the Y-axis, the keyword “labels” is used. Now use scales: : percent to convert the y-axis labels into a percentage. This will scale the y-axis data from decimal to percentage. It simply multiplies the value by 100.
Make a list of frequencies. Create a new figure or activate an existing figure. Make a bar plot using bar() method. Iterate the bar plot and find the height of each patch and use annotate() method to put values in percentages.
It's easiest to calculate the quantities you need beforehand, outside of ggplot, as it's hard to track what ggplot calculates and where those quantities are stored and available.
First, summarize your data:
library(dplyr)
library(ggplot2)
mtcars %>%
count(cyl = factor(cyl), gear = factor(gear)) %>%
mutate(pct = prop.table(n))
#> # A tibble: 8 x 4
#> cyl gear n pct
#> <fct> <fct> <int> <dbl>
#> 1 4 3 1 0.0312
#> 2 4 4 8 0.25
#> 3 4 5 2 0.0625
#> 4 6 3 2 0.0625
#> 5 6 4 4 0.125
#> 6 6 5 1 0.0312
#> 7 8 3 12 0.375
#> 8 8 5 2 0.0625
Save that if you like, or pipe directly into ggplot:
mtcars %>%
count(cyl = factor(cyl), gear = factor(gear)) %>%
mutate(pct = prop.table(n)) %>%
ggplot(aes(x = cyl, y = pct, fill = gear, label = scales::percent(pct))) +
geom_col(position = 'dodge') +
geom_text(position = position_dodge(width = .9), # move to center of bars
vjust = -0.5, # nudge above top of bar
size = 3) +
scale_y_continuous(labels = scales::percent)
If you really want to keep it all internal to ggplot, you can use geom_text
with stat = 'count'
(or stat_count
with geom = "text"
, if you prefer):
ggplot(data = mtcars, aes(x = factor(cyl),
y = prop.table(stat(count)),
fill = factor(gear),
label = scales::percent(prop.table(stat(count))))) +
geom_bar(position = "dodge") +
geom_text(stat = 'count',
position = position_dodge(.9),
vjust = -0.5,
size = 3) +
scale_y_continuous(labels = scales::percent) +
labs(x = 'cyl', y = 'pct', fill = 'gear')
which plots exactly the same thing.
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