How to make a custom hoverinfo lables for Plotly boxplot?

Here is an example using ggplot2, that you can map through to plotly.

I hope it helps point you in the right direction. The latest version of plotly and ggplot2 do now display hover values. My approach has been to create text labels as this allows me to roll into a template function that I can use.

T.

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Graphics Output (ggplot2)

Graphics Output (plotly)

Code Example

require(DAAG)
require(ggplot2)
require(plotly)
data("possum")

dset <- possum
here <- possum$sex == "f"
dname <- as.character(substitute(possum))
xnam <- as.character(substitute(x))
x <- dset[here, "totlngth"]

yLabel <- c("Total length (cm)")

## Pull in boxplot stats for use in mapping data later to boxplot
z <- boxplot.stats(x)
xlim <- range(c(z$stats, z$out))
xlim <- xlim + c(-0.025, 0.05) * diff(xlim)
ylim <- c(0.55, 1.5)

top <- 0.7
chh <- par()$cxy[2]
chw <- par()$cxy[1]

gp <- ggplot(data = possum, aes(y = totlngth, x = ""))
gp <- gp + stat_boxplot(geom = 'errorbar', width = .1)
gp <- gp + geom_boxplot(#width = .3,
                        outlier.color = "blue",
                        outlier.shape = 2)
gp <- gp + stat_summary(fun.y = mean,
                        geom = "point",
                        shape = 5,
                        size = 4)
gp <- gp + xlab(NULL)
gp <- gp + ylab(yLabel)
gp <- gp + theme(axis.ticks.x = element_blank(),
                 panel.grid.major = element_blank(),
                 panel.grid.minor = element_blank(),
                 panel.background = element_blank())

gp <- gp + geom_text(data = data.frame(), aes(x = top + 1.5 * chh,
                                            y = z$stats[5],
                                            label = "Largest value \n(there are no outliers)"
                                            ))

gp <- gp + geom_text(data = data.frame(), aes(x = top + 1.5 * chh,
                                              y = z$stats[4],
                                              label = "upper quartile"
                                              ))

gp <- gp + geom_text(data = data.frame(), aes(x = top + 1.5 * chh,
                                              y = z$stats[3],
                                              label = "median"
                                              ))

gp <- gp + geom_text(data = data.frame(), aes(x = top + 1.5 * chh,
                                              y = z$stats[2],
                                              label = "lower quartile"
                                              ))

gp <- gp + geom_text(data = data.frame(), aes(x = top + 1.5 * chh,
                                              y = z$stats[1],
                                              label = "Smallest value \n(outliers excepted)"
                                              ))
if (!is.null(z$out)) {
  gp <- gp + geom_text(data = data.frame(), aes(x = top + 1.5 * chh,
                                              y = z$out[1],
                                              label = "Outlier \n"
                                              ))
  # Display outlier
  gp <- gp + geom_text(data = data.frame(), aes( x = rep(top - chh, 2),
                                                 y = z$out[1] + .5,
                                                 label = c(format(round(z$out[1], 2)))))

}

av <- mean(z$stats[c(2, 4)])
q1 <- z$stats[2]
q3 <- z$stats[4]
qtop <- q3 + 0.5 * chh


# Largest Value
gp <- gp + geom_text(data = data.frame(), aes( x = rep(top - chh, 2),
                                               y = z$stats[5],
                                               label = c(format(round(z$stats[5], 2)))))


# Upper Quartile
gp <- gp + geom_text(data = data.frame(), aes( x = rep(top - chh, 2),
                                               y = q1,
                                               label = c(format(round(q1, 2)))))

# Lower Quartile
gp <- gp + geom_text(data = data.frame(), aes( x = rep(top - chh, 2),
                                               y = q3,
                                               label = c(format(round(q3, 2)))))

gp

p <- ggplotly(gp)
p

Note: The code above is an evolution from a base graphics package boxplot example in:

• Data Analysis and Graphics Using R, Third Edition By: John Maindonald; W. John Braun

the book covers the base package in great detail, it was published in 2010, still a great source of insight.