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 define your own custom scale, if you like. If you look at the source for scale_fill_manual,

scale_fill_manual
#> function (..., values) 
#> {
#>     manual_scale("fill", values, ...)
#> }
#> <environment: namespace:ggplot2>

it's actually quite simple:

library(ggplot2)

scale_fill_chris <- function(...){
    ggplot2:::manual_scale(
        'fill', 
        values = setNames(c('green', 'blue', 'red', 'orange'), LETTERS[1:4]), 
        ...
    )
}

df1 <- data.frame(Value = c(40, 20, 10, 60), 
                  Type = c("A", "B", "C", "D"))

ggplot(df1, aes(x = Type, y = Value, fill = Type)) + 
    geom_col() + 
    scale_fill_chris()

df2 <- data.frame(Value = c(40, 20, 60), 
                  Type = c("A", "B", "D"))

ggplot(df2, aes(x = Type, y = Value, fill = Type)) + 
    geom_col() + 
    scale_fill_chris()

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)

ggplot(df3, aes(x = Type, y = Value, fill = Type)) + 
    geom_col() + 
    scale_fill_chris()

Answer 2

Another options is to make drop = F the default by defining the default colour scales as follows:

scale_colour_discrete <- function(...)
  scale_colour_manual(..., drop = F)
scale_fill_discrete <- function(...)
  scale_fill_manual(..., drop = F)

That way colours are always consistent for different factors.

Answer 3

make sure you convert that column into Factor first and then create a variable to store the color value for each factor...

df$color <- as.factor(df$color, levels = c(1, 0))
cbPallete <- c("1"= "green", "0"="red")

ggplot(data = df) + geom_bar(x = df$x, 
                             y = df$y,
                             fill = df$color) +
scale_fill_manual(values = cbPallete)

Answer 4

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)