Colorful geom_bar() plot

Question

My data contains only one variable and a daytime column. I want to make a colorful geom_bar() plot. This means that every bar has different color.

Example of data:

daytime price
2000-01-01 30
2000-01-02 34
2000-01-03 29
2000-01-04 31
2000-01-05 38
2000-01-06 41
2000-01-07 31

The geom_bar plot contains 7 bars, once for each day. How can every bar have different colour?

I tried to change the fill:

   geom_bar(stat = "identity", fill = "grey")

How can I do this?

Answer 1

You have to supply the same number of colors for fill= as there are bars in your plot. Here is example using function rainbow() to make colors.

ggplot(df,aes(daytime,price))+
         geom_bar(stat = "identity", fill = rainbow(n=length(df$price)))

Automatically it can be done if you put fill= inside the aes() and then provide row names of your data frame as variable. With guides(fill=FALSE) you can remove legend.

ggplot(df,aes(daytime,price,fill=rownames(df)))+
       geom_bar(stat = "identity")+guides(fill=FALSE)