Samo Jerom Samo Jerom - 3 months ago 51
R Question

Plot multiple boxplot in one graph

I saved my data in as a

.csv
file with 12 columns. Columns two through 11 (labeled
F1, F2, ..., F11
) are
features
.
Column one
contains the
label
of these features either
good
or
bad
.

I would like to plot a
boxplot
of all these 11 features against the
label
, but separate by
good
or
bad
. My code so far is:

qplot(Label, F1, data=testData, geom = "boxplot", fill=Label,
binwidth=0.5, main="Test") + xlab("Label") + ylab("Features")


However, this only shows
F1
against the
label
.

My question is: How to show
F2, F3, ..., F11
against the
label
in one graph with some
dodge position
? I have normalized the features so they are in the same scale within [0 1] range.

The test data can be found here. I have drawn something by hand to explain the problem (see below).

hand-drawn boxplot example

Answer

You should get your data in a specific format by melting your data (see below for how melted data looks like) before you plot. Otherwise, what you have done seems to be okay.

require(reshape2)
df <- read.csv("TestData.csv", header=T)
# melting by "Label". `melt is from the reshape2 package. 
# do ?melt to see what other things it can do (you will surely need it)
df.m <- melt(df, id.var = "Label")
> df.m # pasting some rows of the melted data.frame

#     Label variable      value
# 1    Good       F1 0.64778924
# 2    Good       F1 0.54608791
# 3    Good       F1 0.46134200
# 4    Good       F1 0.79421221
# 5    Good       F1 0.56919951
# 6    Good       F1 0.73568570
# 7    Good       F1 0.65094207
# 8    Good       F1 0.45749702
# 9    Good       F1 0.80861929
# 10   Good       F1 0.67310067
# 11   Good       F1 0.68781739
# 12   Good       F1 0.47009455
# 13   Good       F1 0.95859182
# 14   Good       F1 1.00000000
# 15   Good       F1 0.46908343
# 16    Bad       F1 0.57875528
# 17    Bad       F1 0.28938046
# 18    Bad       F1 0.68511766

require(ggplot2)
ggplot(data = df.m, aes(x=variable, y=value)) + geom_boxplot(aes(fill=Label))

boxplot_ggplot2

Edit: I realise that you might need to facet. Here's an implementation of that as well:

p <- ggplot(data = df.m, aes(x=variable, y=value)) + 
             geom_boxplot(aes(fill=Label))
p + facet_wrap( ~ variable, scales="free")

ggplot2_faceted

Edit 2: How to add x-labels, y-labels, title, change legend heading, add a jitter?

p <- ggplot(data = df.m, aes(x=variable, y=value)) 
p <- p + geom_boxplot(aes(fill=Label))
p <- p + geom_jitter()
p <- p + facet_wrap( ~ variable, scales="free")
p <- p + xlab("x-axis") + ylab("y-axis") + ggtitle("Title")
p <- p + guides(fill=guide_legend(title="Legend_Title"))
p 

ggplot2_geom_plot

Edit 3: How to align geom_point() points to the center of box-plot? It could be done using position_dodge. This should work.

require(ggplot2)
p <- ggplot(data = df.m, aes(x=variable, y=value)) 
p <- p + geom_boxplot(aes(fill = Label))
# if you want color for points replace group with colour=Label
p <- p + geom_point(aes(y=value, group=Label), position = position_dodge(width=0.75))
p <- p + facet_wrap( ~ variable, scales="free")
p <- p + xlab("x-axis") + ylab("y-axis") + ggtitle("Title")
p <- p + guides(fill=guide_legend(title="Legend_Title"))
p 

ggplot2_position_dodge_geom_point