Is there an equivalent in ggplot to the varwidth option in plot?

Question

I am creating boxplots using ggplot and would like to represent the sample size contributing to each box. In the base plot function there is the varwidth option. Does it have an equivalent in ggplot?

For example, in base plot

data <- data.frame(rbind(cbind(rnorm(700, 0,10), rep("1",700)),
                         cbind(rnorm(50, 0,10), rep("2",50))))
data[ ,1] <- as.numeric(as.character(data[,1]))
plot(data[,1] ~ as.factor(data[,2]), varwidth = TRUE)

Answer 1

Not elegant but you can do that by:

data <- data.frame(rbind(cbind(rnorm(700, 0,10), rep("1",700)),
                         cbind(rnorm(50, 0,10), rep("2",50))))
data[ ,1] <- as.numeric(as.character(data[,1]))
w <- sqrt(table(data$X2)/nrow(data))
ggplot(NULL, aes(factor(X2), X1)) + 
  geom_boxplot(width = w[1], data = subset(data, X2 == 1)) +
  geom_boxplot(width = w[2], data = subset(data, X2 == 2))

If you have several levels for X2, then you can do without hardcoding all levels:

ggplot(NULL, aes(factor(X2), X1)) + 
  llply(unique(data$X2), function(i) geom_boxplot(width = w[i], data = subset(data, X2 == i)))

Also you can post a feature request: https://github.com/hadley/ggplot2/issues

Answer 2

The current versions of ggplot2 (V 2.1.0) now contains a varwidth option:

data <- data.frame(rbind(cbind(rnorm(700, 0,10), rep("1",700)),
                     cbind(rnorm(50, 0,10), rep("2",50))))
data$X1 <- as.numeric(as.character(data$X1))
ggplot(data = data, aes(x = X2, y = X1)) + 
    geom_boxplot(varwidth = TRUE)