CODEWITHSUNDEEP
rggplot2
Oliver
Oliver

Reputation: 3682

Consistently define fill color for bar chart

I have a dataset as this, and my goal is to make a bar chart and fill positive value with green, negative value with red:

df = data.frame(exp=c("A", "B", "C"), val = c(0.3,0.2,-0.1))
df$pos = df$val > 0
ggplot(df, aes(x=exp, y=val, fill=pos)) + geom_bar(stat="identity") + scale_fill_manual(values=c("red", "green"), guide=FALSE)

Above plot works as I expected. However, if my dataset happens to be all positive values:

df$val = c(0.3, 0.4, 0.5)
df$pos = df$val > 0

The same plotting will plot all positive value as "red" instead of "green", which is not what I want or expect. How do I fix this? TIA.

Upvotes: 0

Views: 86

Answers (1)

Didzis Elferts
Didzis Elferts

Reputation: 98429

Inside the scale_fill_manual() add that you need TRUE values as green and FALSE as red. If you just name color names then in case of only positive values there is only one level (TRUE) and the first of two colors is used (is your case it is red).

ggplot(df, aes(x=exp, y=val, fill=pos)) + geom_bar(stat="identity") + 
  scale_fill_manual(values=c("FALSE"="red", "TRUE"="green"), guide=FALSE)

Upvotes: 2

Related Questions