ggplot2: Fix colors to factor levels

Question

I\'m working on a larger project for which I am creating several plots in ggplot2. The plots are concerned with plotting several different outcomes across several different

Answer 1

You could make a custom plot function (including scale_fill_manual and reasonable default colours) in order to avoid repeating code:

library(ggplot2)
custom_plot <- function(.data,
  colours = c("A" = "green", "B" = "blue", "C" = "red", "D" = "grey"))  {
  ggplot(.data, aes(x=Type, y=Value, fill= Type)) + geom_bar(stat="identity") +
   scale_fill_manual(values = colours)
}

df1 <- data.frame(Value=c(40, 20, 10, 60), Type=c("A", "B", "C", "D"))
df2 <- data.frame(Value=c(40, 20, 60), Type=c("A", "B", "D"))
df3 <- data.frame(Value=c(40, 20, 10, 60), Type=c("A", "B", "C", "D"))
df3$Type <- factor(df3$Type, levels=c("D", "C", "B", "A"), ordered=TRUE)

custom_plot(df1)
custom_plot(df2)
custom_plot(df3)