Fill and dodge boxplots by group on a continuous x axis

user_4561056 0
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I have been having issues with what seems to be a simple thing to do: grouped boxplots with a continuous x axis.

Here is come minimal data data:

df <- cbind(expand.grid(x=1:10, rep=1:20, fill=c("A", "B")), y=runif(400))

And here is what I want; you will see I have forced the x axis to be discrete:

ggplot(df, aes(x=as.factor(x), y=y,  fill=fill)) + geom_boxplot()

enter image description here

This is what I get when I leave x as continuous, without a grouping:

ggplot(df, aes(x=x, y=y,  fill=fill)) + geom_boxplot()

enter image description here

When I add a grouping, the color disappears:

 ggplot(df, aes(x=x, y=y, group=x, fill=fill)) + geom_boxplot()

enter image description here

To be clear, what I would want in geom_point would be:

ggplot(df, aes(x=x, y=y, group=x, color=fill)) + geom_point(position=position_dodge(width=.7))

enter image description here

...but if I try to set a dodge in boxplot:

ggplot(df, aes(x=x, y=y, color=fill)) + geom_boxplot(position=position_dodge(width=.7))

enter image description here

Any tips? I have tried searching around: this question addressed continuous boxplots, but without the coloring issue; this question makes me wonder if i need to set an interaction, but doesn't seem to get the desired results. Any help would be hugely appreciated!

boxplot ggplot2 grouping plot r
2 Answers

Here is a version that works, custom built for your own cut sizes:

Take the original df:

{df <- cbind(expand.grid(x=1:10, rep=1:20, fill=c("A", "B")), y=runif(400))}

Use cut() to define where you want your x groups and use "dodge2" to position your graphs:

{ggplot(df, aes(x = cut(x, 5), y = y, fill = fill)) +
        geom_boxplot(position = "dodge2", outlier.alpha = 0.1)}

Boxplot with 5 custom groups with equal cuts between 1:10 Boxplot with 5 custom groups with equal cuts between 1:10

user_112709360
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