Change bar plot colour in geom_bar with ggplot2 in r

Question

I have the following in order to bar plot the data frame.

c1 <- c(10, 20, 40)
c2 <- c(3, 5, 7)
c3 <- c(1, 1, 1)
df <- data.frame(c1, c2, c3)
ggplot(data=df, aes(x=c1+c2/2, y=c3)) +
  geom_bar(stat="identity", width=c2) +
  scale_fill_manual(values=c("#FF6666"))

I end up having only grey bars: Grey bars for bar plot

I would like to change the color of the bar. I already tried different scale_fill_manual from http://www.cookbook-r.com/Graphs/Colors_(ggplot2)/ but still have grey bars.

Thank you for your help.

Reckless

If you only want to change the general colors of bars, without differences between bars, write it directly in geom_bar(): geom_bar(stat="identity", width=c2, color = "#FF6666") – Evasive

So this time I only have the contour of color="#FF6666", the filling stays grey. Now if I put : ggplot(data=df, aes(x=c1+c2/2, y=c3, fill=c3)) + geom_bar(stat="identity", width=c2) I then have a blue-ish color filled, but again, I do not get to choose manually. – Reckless

geom_bar(stat="identity", width=c2, fill = "#FF6666") for same fill for all the bars. Use scale_fill_manual(values=c("#FF6666")) if you want to set color by a variable (category). – Evasive

do you get a red color? Because what you just wrote is what I have put in my question and I still get grey. I also tried ggplot(data=df, aes(x=c1+c2/2, y=c3, fill=c3)) + geom_bar(stat="identity", width=c2) + scale_fill_manual(values=c("#FF6666")) but this gives me the error Error : Continuous value supplied to discrete scale – Reckless

I have a red color using ggplot(data=df, aes(x=c1+c2/2, y=c3)) + geom_bar(stat="identity", width=c2, fill = "#FF6666") which is similar to ggplot(data=df, aes(x=c1+c2/2, y=c3)) + geom_bar(stat="identity", width=c2, fill = "red") – Evasive

ok, this time with your last code it works. Thank you so much. Can you put that as an answer maybe so I can mark as "answered"? – Reckless

Already did with detailed information. – Evasive

I also have issues, but with legend. It either has not corresponding colors, or the bars themselves have wrong fill color. – Cringe

Answer 1

If you want all the bars to get the same color (fill), you can easily add it inside geom_bar.

ggplot(data=df, aes(x=c1+c2/2, y=c3)) + 
geom_bar(stat="identity", width=c2, fill = "#FF6666")

Add fill = the_name_of_your_var inside aes to change the colors depending of the variable :

c4 = c("A", "B", "C")
df = cbind(df, c4)
ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = c4)) + 
geom_bar(stat="identity", width=c2)

Use scale_fill_manual() if you want to manually the change of colors.

ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = c4)) + 
geom_bar(stat="identity", width=c2) + 
scale_fill_manual("legend", values = c("A" = "black", "B" = "orange", "C" = "blue"))

Evasive

I like the color choice – Shakira

Answer 2

You could also directly assign your x variable to the fill aesthetic as a factor like this:

c1 <- c(10, 20, 40)
c2 <- c(3, 5, 7)
c3 <- c(1, 1, 1)
df <- data.frame(c1, c2, c3)
library(ggplot2)
ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = factor(c1+c2/2))) +
  geom_bar(stat="identity", width=c2)

When you know what these factors are called (this case: 11.5, 22.5, 43.5), you can simply change its colors using scale_fill_manual with values like this:

library(ggplot2)
ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = factor(c1+c2/2))) +
  geom_bar(stat="identity", width=c2) +
  scale_fill_manual("Legend", values = c("11.5" = "red", "22.5" = "green", "43.5" = "blue"))

^{Created on 2023-01-26 with reprex v2.0.2}

Faunus