Histogram with weights in R

Question

I need to plot a weighted histogram of density rather than frequency. I know that freq = FALSE is available in hist() but you can't specify weights. In ggplot2 I can do this:

library(ggplot2)
w <- seq(1,1000)
w <-w/sum(w)
v <- sort(runif(1000))

foo <- data.frame(v, w)

ggplot(foo, aes(v, weight = w)) + geom_histogram()

But where is the equivalent of freq = FALSE?

Solution

By default, geom_histogram() will use frequency rather than density on the y-axis. However, you can change this by setting your y aesthetic to ..density.. like so:

ggplot(foo, aes(x = v, y = ..density.., weight = w)) + geom_histogram()

This will produce a weighted histogram of v with density on the y-axis.

You can also do this with the freq argument in weighted.hist() from the plotrix package:

library(plotrix)
with(foo, weighted.hist(v, w, freq = FALSE))