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 weight
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))
