Grouped Boxplot on discrete x-axis in R-CodePudding

I have a dataframe similar to the below:

df
variable   n        value
1   x_1 200 2.883524e 22
2   x_1 200 6.228677e 19
3   x_1 200 1.152941e 23
4   x_1 200 2.873297e 20
5   x_1 200 2.860104e 22
6  x_2 200 2.756752e 04
7  x_2 200 6.430455e 02
8  x_2 200 5.933116e 09
9  x_2 200 5.935287e 09
10  x_2 200 1.283504e 06
11  x_1 250 2.137800e 06
12  x_1 250 1.439365e 04
13  x_1 250 5.685357e 10
14  x_1 250 5.727160e 10
15  x_1 250 4.151983e 08
16  x_2 250 5.181344e 06
17  x_2 250 1.899797e 04
18  x_2 250 5.301975e 10
19  x_2 250 5.434231e 10
20  x_2 250 2.158825e 09

I am trying to develop a grouped box plot with n on the x-axis, value on the y-axis (using scale_y_log10()), and variable as the fill boxplots. However, I am struggling to actually plot each value of n on the x_axis and grouping the box plots. I currently have:

ggplot(data = df, mapping = aes(x = n, y = value, fill = variable))   
  geom_boxplot(aes(group = cut_width(variable, 0.25)))  
  scale_y_log10()

but am struggling to get the results I was hoping for, is it possible to develop this type of box plot on a continuous x-axis and group by variable?

Thanks in advance.

CodePudding user response：

You could make the x axis discrete, simply feeding in the extra factor levels that you want to make the appropriate breaks in the x axis:

ggplot(data = df, aes(x = factor(n, levels = c(200, 250, 300)), y = value))   
  geom_boxplot(aes(fill = variable))  
  scale_y_log10()  
  scale_x_discrete(drop = FALSE, name = 'n')