r - Custom ggplot2 axis and label formatting

Question

I'm trying to draw labels which look informative, clear and tidy.

I was following example and raised one more question about label and axis formatting.

For example, I have sales data which includes Brand, Categories and Expenditure in EUR. When sum of EUR is big (millions or more) labels look really hard to read and not informative.

As a result, x-axis is in Scientific notation and also looks really uncleanly.

I've manage to format labels in custom way: it shows Eur in thousands. geom_text(aes(label= paste(round(EUR/1000,0),"€"), y=pos), colour="white") Is there an easier or automated way?

As Scientific notation looks really unclear, for axis I tried using scale_y_continuous(formatter = "dollar"), but this seems do not work. Moreover, I was unable to find if there is Eur also implemented instead of dollar. I believe that it would be the best to show y-axis in thousands. Any solutions?

Also, I enclose reproducible example:

library(plyr)
library(dplyr)
library(ggplot2)
library(scales)


set.seed(1992)
n=68

Category <- sample(c("Black", "Red", "Blue", "Cyna", "Purple"), n, replace = TRUE, prob = NULL)
Brand <- sample("Brand", n, replace = TRUE, prob = NULL)
Brand <- paste0(Brand, sample(1:5, n, replace = TRUE, prob = NULL))
EUR <- abs(rnorm(n))*100000

df <- data.frame(Category, Brand, EUR)


df.summary = df %>% group_by(Brand, Category) %>% 
  summarise(EUR = sum(EUR)) %>%   # Within each Brand, sum all values in each Category
  mutate( pos = cumsum(EUR)-0.5*EUR)



ggplot(df.summary, aes(x=reorder(Brand,EUR,function(x)+sum(x)), y=EUR, fill=Category)) +
  geom_bar(stat='identity',  width = .7, colour="black", lwd=0.1) +
  geom_text(aes(label=ifelse(EUR>100,paste(round(EUR/1000,0),"€"),""),
                y=pos), colour="white") +
  coord_flip()+
  labs(y="", x="")

Answer 1

You can set the prefix in dollar_format for euros instead of dollars:

scale_y_continuous(labels=dollar_format(prefix="€")) +

That takes care of the scientific notation issue.

To get everything in thousands, you could just divide by 1000 when you create the summary. To reduce clutter, you could leave out the euro symbol in the bar labels, but I've kept the symbol in the example below:

df.summary = df %>% group_by(Brand, Category) %>% 
  summarise(EUR = sum(EUR)/1000) %>%   # Within each Brand, sum all values in each Category
  mutate( pos = (cumsum(EUR)-0.5*EUR))

ggplot(df.summary, aes(x=reorder(Brand,EUR,function(x)+sum(x)), y=EUR, fill=Category)) +
  geom_bar(stat='identity',  width = .7, colour="black", lwd=0.1) +
  geom_text(aes(label=ifelse(EUR>100,paste0("€", round(EUR,0)),""),
                y=pos), colour="white") +
  scale_y_continuous(labels=dollar_format(prefix="€")) +
  coord_flip()+
  labs(y="Thousands of €", x="")