Lollypop plot with a Customizes Colour in R

April 14, 2022

I have a data frame that consists of three (3) variables (Methods, lb and RMSE).

df1 <- data.frame(Methods = c('b', 'a', 'c', 'd', 'e'), lb = c(9, 7, 9, 4, 9), RMSE = c(0.26177952, 0.11294586, 0.02452239, 0.08290467, 0.41488542))
df1

  Methods lb       RMSE
1       b  9 0.26177952
2       a  7 0.11294586
3       c  9 0.02452239
4       d  4 0.08290467
5       e  9 0.41488542

I want the Methods(a, b, c, d, e) to be arranged on the x-axis, the height of the lollypop plot to correspond to the values of RMSE while the colours on the lillyplot to vary among the lb variable.

I have tried this

df1 |>
  ggplot2::ggplot(ggplot2::aes(x = Methods, y = RMSE)) + ggplot2::geom_point(size = 4) + 
ggplot2::geom_segment(ggplot2::aes(x = Methods, xend = Methods, yend = RMSE, y = 0)) + 
ggplot2::scale_fill_manual(values = c("green", "yellowgreen", "yellow", "orange", "red"))

I got this

df1 |>
  ggplot2::ggplot(ggplot2::aes(x = Methods, y = RMSE)) + ggplot2::geom_point(size = 4) + 
ggplot2::geom_segment(ggplot2::aes(x = Methods, xend = Methods, yend = RMSE, y = 0)) + 
ggplot2::scale_fill_manual(values = c("green", "yellowgreen", "yellow", "orange", "red")) + 
ggplot2::theme_bw() + ggplot2::scale_colour_gradientn(colours = rev(rainbow(5)))

When I changed from manual the image is still the same without colour.

What I want

I want the pop with colours such that I can customize the pop’s colours

>Solution :

First of all, you don’t really need to do ggplot:: in all functions. It’s just a syntax to make sure the functions you use are from the specific package package:: you want. For ggplot functions, I’m pretty sure there’s no conflicting function names.

Second, if you want scale_fill_manual to work, you need to use aes(fill = var) in geom_function() or ggplot().

If you want the fill or colour to apply to all geom_*() layers, use ggplot(aes(fill = var)).
Otherwise, only use it in the desired geom_*() layer, which is in this case, in geom_point(aes(color = var)) (Note that in my code, I placed it in ggplot, so geom_segment is also coloured accordingly).

Third, since you’re colouring geom_point, you should use scale_color_manual instead of scale_fill_manual (and also aes(color = var).

library(ggplot2)

df1 <- data.frame(Methods = c('b', 'a', 'c', 'd', 'e'), lb = c(9, 7, 9, 4, 9), RMSE = c(0.26177952, 0.11294586, 0.02452239, 0.08290467, 0.41488542))

df1 |>
  ggplot(aes(x = Methods, y = RMSE, col = Methods)) + geom_point(size = 4) + 
  geom_segment(aes(x = Methods, xend = Methods, yend = RMSE, y = 0)) + 
  scale_color_manual(values = c("green", "yellowgreen", "yellow", "orange", "red")) + 
  theme_bw()